One way to do that is to look at a variety of stats, like CSW% or xwOBA. Yet, those stats look at a subset of results, whether it be called or swinging strikes, or the result of a plate appearance. What they don’t account for, is how much a result is worth in how it changes the structure of the at-bat.

Intuitively, we know that 0-2 counts are much better than 3-0 counts for a pitcher; after all, you’re only one pitch away from a strikeout. What Run Value tries to do is account for the change in count states, like going from 0-0 to 0-1 or 2-2 to 3-2, by how run potential changes from state to state, usually on a pitch type level.

Take this 99-mph Ahn Woo-jin fastball that lands out of the zone. That’s a tough pitch to hit velocity-wise, but since it’s outside of the zone, the likelihood of allowing a hitter-friendly outcome to Kim Jae-hwan rises (FWIW, Ahn’s fastball has the fifth-best RV/100 among fastballs). We want a way to measure how effective a pitch is, rather than a measure based on pitch characteristics like velocity, spin, and movement. With Run Value, this is a “bad” pitch because it takes the count from 2-2 to 3-2.

You can find the MLB leaders on Baseball Savant, where they define Run Value as “the run impact of an event based on the runners on base, outs, ball, and strike count”.  This project was inspired by Ethan Moore’s quest to create an xRV metric for the 2020 season, which you can find here.

With the nearly 30,000 pitches that I charted from the 2020 KBO season, I created Run Values for the KBO and the pitches that I tracked and will be detailing that process and some of my findings in this article. You can find the code for this project here and can check out the leaderboard that I added to the KBO Wizard. Back in July, I wrote about some of the Nastiest Pitches in the KBO, but using Run Values, we can see which pitches were the most effective.

The wOBA weights referenced in this article are from Statiz, and you can find their version of a ‘GUTS!’ page here.

I have previously detailed my process of calculating wOBA and Estimated xwOBA (ExwOBA) here, and I base my Run Values per count on ExwOBA. The first step of calculating Run Value is figuring out how the average result (ExwOBA in this case) changes by count state in the KBO. From there, it’s a matter of translating the ExwOBA into a measure of runs; fortunately, we can translate wOBA into Weighted Runs Above Average (wRAA), a measure of how many runs a hitter contributed, with zero as the league average.

The equation is relatively simple, involving the wOBA value, league average wOBA, and the wOBA scale: wRAA = ((wOBA – league wOBA) / wOBA scale) × PA.

We apply the formula to our values and return the wRAA value for each count state (Statiz lists the KBO average wOBA as 0.347. However, the charted data skews toward the best pitchers in the KBO, resulting in an average of 0.339, which is the value used for the KBO average wOBA).

The next step is figuring out how a ball and strike changes wRAA in each count state. To do that, we take the wRAA for an 0-1 count (0.024) and subtract the wRAA for a 0-0 count (0.032). In this instance, the value of throwing a strike on an 0-0 count, leading to a 0-1 count is -0.008. This makes sense; throwing a first-pitch strike is detrimental to a hitter (hence the negative value), but not by too much; the KBO has a high Ball in Play%, so first-strikes aren’t as crucial as they maybe in MLB.. The value of throwing a strike or ball in each count is listed below.

About 95% of these values make sense: throwing strikes is good for a pitcher (negative values), and throwing balls is bad (positive values). However, there are a few oddities, notably the value of throwing a strike in a 2-0 count, which is worth 0.008 wRAA, a bad result for a pitcher. The ExwOBA in a 2-0 count is slightly lower than it is in a 2-1 count, which is responsible for this discrepancy. Given that the K% in the KBO is significantly lower than MLB, I’m not surprised that there’s very little difference between 2-0 and 2-1 counts.

Another strange result is that throwing a ball in an 0-2 count is a good result for a pitcher with a -0.112 value, though it pales in comparison to the -0.288 for throwing a strike (which leads to a strikeout). My thought here is that 0-2 counts increase the likelihood of a bad swing/batted ball, while a called ball is designed to get a chase swing. If the hitter doesn’t swing, a 1-2 count is still a tough situation.

There’s another strange result where a ball in a 1-0 count is worth -0.009, good for the pitcher. The ExwOBA in 2-0 counts is slightly lower than 1-0 counts, something that I chalk up to the “small” data set of 30,000 pitches that I charted.

On the whole, these results are similar to ones found by Dan Meyer. The KBO and MLB have different play styles (which I believe accounts for some of the stranger results). I proceeded with this project after exploring why those results occurred.

From there, it was a matter of re-structuring the results and joining them to my charted data. Once we did that, we were able to produce final Run Value results for pitchers and their pitch types in the KBO from the 2020 season. The leaders in Run Value per 100 pitches are shown below.

Here is a representation of Run Value on every charted KBO pitch; it’s interesting to note that pitches on the corners of the zone fared the best consistently. After all, if you get a swing that far out, it’s bound to be a good result for a pitcher. The effect of called strikes and fouls (which were treated as a strikes for this project) also help to keep the strike zone a place worth attacking.

Here’s a breakdown of some of the top pitches in the KBO by RV/100.

Aaron Brooks’ slider leads the way by a large margin, with a -6.7 RV/100. It’s worthy of the title, with a 23.7% SwStr% (highest on an individual pitch in the KBO), a 0.224 ExwOBA, and a 61% GB%. Hitters stood no chance against it all year long, especially when he paired it with his changeup. It was most effective working down-and-away from RHH or on the edges of the zone against LHH.

Dan Straily’s slider narrowly beats out two other breaking pitches for the second spot, with a -5.9 RV/100. He rode the pitch to 205 strikeouts in 2020 (making him the world-leader in Ks in 2020), and you likely saw his highlights all over Twitter back in May. He threw it 34% of the time, netting a 20.6% SwStr%.

He threw it in all kinds of high leverage situations, like 40% of the time in 0-2 counts. Throwing the pitch in those situations, and getting strikes, is why his slider grades out at the second-best pitch in the KBO. Against LHH, he worked his slider on the edges of the zone while it acted as a whiff pitch down-and-away from RHH.

Jake Brigham’s slider comes in fourth place here at -5.9 RV/100. Interestingly, his curveball is fifth at -5.5 RV/100. But, despite those two stellar pitches, Brigham wasn’t re-signed by the Kiwoom Heroes (though he has since joined the CPBL in Taiwan) due to a poor track record of health in 2020. Regardless, his breaking pitches amounted to 43% of his total pitches and were phenomenal offerings. I thought he should try to increase his usage of the pitches, and we’ll see if he makes any adjustments in the CPBL.

Fourth-place belongs to Chris Flexen and his curveball. The 26-year-old Flexen signed with the Seattle Mariners following his stellar 2020 season, and the curveball was part of the reason why; it sported a 22% SwStr%, and a 0.197 ExwOBA; that’s pretty good.

While his curveball velocity held at about 76 mph, the Mariners liked how the shape of his curveball changed in the KBO, becoming a pitch that may play better against MLB hitters than his original offering. The pitch was extremely effective down against LHH, while he showed the ability to throw it for whiffs or called strikes against RHH.

This stat is modeled on the Run Value and RV/100 hosted on Baseball Savant, though the two shouldn’t be compared to each other (naturally, given that they are for two separate leagues). In 2019 (using the full MLB season to comp to the full KBO season), the best RV/100 belonged to Felipe Vazquez’s slider at -6.2. The highest cumulative total was Gerrit Cole’s fastball at -36 Run Value; in the KBO, the lowest cumulative Run Value belonged to Raúl Alcántara’s fastball at -61 since he threw it 1417 times at a -4.3 RV/100 clip.

This is not a perfect stat, but another tool to help facilitate evaluating KBO pitches. While 0 RV/100 is an average pitch, many of the pitches in the KBO Wizard will register with an RV/100 better than 0 since I focused on charting the good pitchers, not the below-average pitchers. This stat is best used as a comparison to other pitchers and their pitches.

You can find a full leaderboard of Run Values and RV/100 on the KBO Wizard.

View more analysis of Flexen’s season in the KBO here and check out his player page on the KBO Wizard. And enjoy this clip of his fastball and curveball.

Check out Kim Ha-seong player profile on the KBO Wizard and enjoy this 105 mph HR that he hit off of Chris Flexen on September 27th.

As we see time and time again in the MLB playoffs, reliable starting pitching is a prerequisite to being a true contender and can carry you all the way, as the Washington Nationals proved in 2020. Kiwoom’s offense is loaded, with the quartet of Kim Ha-seong, Addison Russell, Lee Jung-hoo, and Park Byung-ho one of the best in the KBO and their bullpen has been good, ranking 1st with a 4.10 bullpen ERA.

The starting pitching staff is where the questions start to emerge. Eric Jokisch is an ace, with a 2.25 ERA and 3.66 FIP, both top-seven marks in the KBO. Number two starter, Jake Brigham, has been up and down this season thanks to some injuries but has posted an ERA of 2.96 and 3.84 the last two seasons. Those two should be able to go toe-to-toe with any other duo in the league, but that’s the problem, the rest of the KBO’s best aren’t limited to a strong duo and Kiwoom ranks 7th with a 4.69 starting pitcher ERA.

The NC Dinos can run out Koo Chang-mo, Drew Rucinski, and Mike Wright. The Kia Tigers can roll out Aaron Brooks, Drew Gagnon, and Im Ki-young. The LG Twins have Casey Kelly, Tyler Wilson, and Im Chan-hyu. The Doosan Bears have Raúl Alcántara, Chris Flexen (when healthy), and some options. The Samsung Lions are solid with Ben Lively, Won Tae-in, and David Buchanan.

That’s where Lee Seung-ho becomes crucial to Kiwoom’s success. The Heroes don’t need him to be better than guys like Mike Wright or Tyler Wilson; they just need him to keep them within striking distance for the offense to go to work. But is Lee capable of being a reliable option for the Heroes? I think he is.

Lee Seung-ho is a 21-year-old LHP for the Heroes, in his third season with Kiwoom. Long story short, he has not been good this year, giving up an ERA of 5.79 and FIP of 5.18 in 65.1 IP in 2020. That’s not promising, but after having watched Lee’s last 445 pitches, I believe there’s more to the story.

I took Lee’s game log from myKBO.com and broke down his results by month. As you can see, there’s been a stark difference in Lee’s success from month-to-month. In May and July, he’s been horrendous, allowing 35 earned runs in 31.1 innings, good for a cumulative 10.05 ERA. In June and August, he’s been a completely different pitcher, allowing just 8 runs over 41 innings, resulting in a 1.76 ERA.

If Kiwoom gets the Lee Seung-ho of June and August thus far, they’re set for the playoffs. If they get May and July Lee, they don’t stand much of a chance. So, what’s led to that huge chasm in Lee’s results, and is there any hope that he can continue to trend towards his June/August results?

I think there is. For starters, there was no drastic difference in the level of competition that he faced from month-to-month as he’s faced a variety of teams. He’s silenced NC, Doosan, and KT (once) and got destroyed by SK, Kia, and KT (twice), so there’s no rhyme or reason there. Now that we’ve established that the level of competition didn’t unduly impact Lee’s success, we can start to explore Lee as a pitcher.

In the months that he’s been successful, Lee has done a good job of limiting walks, hits, and HRs, which makes sense. Taking a look at the advanced stats that I’ve calculated from charting Lee’s games, the biggest difference from June/August to July is his Whiff% which was around 27-30% when he’s been successful and about 18% in July when he got shelled. We can also see that, while his hard contact% is at a whooping 50% in August (12 IP), the ball has been hit on the ground a lot, giving up just one HR and nearly three and a half groundouts to every one flyout. That works; if you’re giving up hard contact, you want it to be groundballs.

But those are still results-based stats. Anyone could tell you that getting more swings-and-misses and groundballs is a recipe for success. But to determine whether Lee can be successful, we need to know HOW he’s getting good results and if it’s sustainable.

The first place I started was with his approach and pitch usage. Lee throws four-pitches, a 4-Seam fastball, changeup, curveball, and a slider. My immediate question was whether or not a velocity dip was to blame for his July struggles; I don’t think it was. His fastball averaged 86.3 mph in June and 86.4 mph in July while ticking up to 87.3 so far in August.

Without any major velocity fluctuations, the only real change is that he threw his fastball more in July while decreasing his slider usage from 27% in his successful months to 19% in July. That’s a pretty decent shift and we’ll jump into that more in a minute, but I want to take a slight detour before breaking that down.

If you’re unfamiliar with these zones, they’re the ones that @tangotiger has talked about, providing another way to examine where the pitcher is throwing the ball. His tweet is simple and does a good job of explaining it, but throwing in the Heart of the zone is dangerous while the Shadow and Chase zones are where most pitchers live.

Lee Seung-ho actually has a pretty big shift in his approach month-to-month from this point of view. His Heart% has dropped from 28% in June to 16% in July and down to 13% in August, which has been matched with about 6% increases in the Shadow and Chase zones. That starts to make sense with his increase in K/9 from 5.0 in June to 7.8 in July and now 8.2 K/9 so far in August; there’s a reason it’s called the “Chase” zone.

Okay, so we’ve established that Lee has started to throw more pitches on the edges of the zone, helping his K/9 numbers and allowing fewer hard-hit fly balls. This approach shift would also explain the drop in Strike% that Lee saw from 71% in June to about 63% in July/August. If you were really paying attention, you’d remember that his called strike (CS%) numbers also went up from 16% in June to 20% in August.

Now this is where we start to dive into his individual pitches and how their usage/approach has informed his success.

We’ll start with Lee’s fastball which, at about a 47% usage rate, is his most heavily used pitch. In the June start of Lee’s that I saw, its usage was abnormal, getting a Whiff% of 25% off of a Swing% of 63%, much higher that the other two months. But it’s the CS% of 27.3% in August that really impresses me; in July his 4-Seam CS% was just 19%, while his Whiff% compensated for his CS% of 21% back in June. To me, this indicates that he’s moved his primary fastball location out of the middle of the plate and has started to attack the edges of the zone more against hitters.

You can see that here with a plot of Lee’s pitch locations. In June, he was throwing everything in the middle of the zone, but in July and August, he started to focus on the edges of the zone, getting more and more called strikes.

In addition to his fastball, Lee has gotten better at painting his changeup on the outside corner against RHH, with his CS% of 16.7% a massive increase over the 3.3% it was back in July. His changeup usage on the corners has also influenced his Whiff% and the increase in his GO/FO rate.

But I believe that the biggest driver of Lee’s success in June and August has been his slider and how his changeup sets it up.

I mentioned Lee’s increased slider usage earlier, noting how he went from throwing it 28% of the time in June to 19% in July and back up to 27% in August. With that, something interesting has happened to the results that Lee gets on his slider; his strike% on sliders has plummeted, falling from 75% in June and 71% in July to just 57% in August. Yet, his Whiff% has risen up to 46%, compensating for just a 11% CS%.

This appears to be intentional, as Lee has been consistently burying his slider in the dirt against RHH and away from LHH, whereas in July and June he threw it more in the zone. Keeping his slider down has also resulted in 6 groundouts and no flyouts in August.

Lee’s slider has proved to be an extremely difficult pitch to hit with the way it breaks over the plate, for both RHH and LHH. His changeup breaks to Lee’s arm side (towards LHH and away from RHH) while his slider does the opposite, sweeping across the plate. With a mere couple mph separating the two pitches, it can be really tough to distinguish them from each other.

Consistently locating his slider down as his swing and miss pitch has freed him up to make the most of his fastball and changeup in the Shadow and Chase zone. For Lee to continue to succeed, he should continue to throw his slider around 30%, his changeup around 15% of the time, and fill in the rest with his fastball and curveball.

While he has been up-and-down this season, there seems to be a clear connection between the pitches that Lee is throwing and where he’s throwing them and how well he’s done in games. With a slider/changeup heavy attack, I think that Lee Seung-ho can be a successful and consistent pitcher for the Kiwoom Heroes, which would bolster their playoff chances immensely.

If you’re interested in doing some more research into Lee Seung-ho or any KBO pitchers, check out the KBO Wizard, a tool that I created to host the 7,000+ pitches of KBO action that I’ve charted.

Here’s how he’s done it and what you can expect from Aaron Brooks when he’s on the mound for the Kia Tigers.

Aaron Brooks is a 30-year-old RHP who was drafted by the Kansas City Royals in 2011 in the 9th-round out of California State San Bernardino. Throughout his MLB career, he bounced around the league, pitching for the Royals, the Athletics, and the Orioles before jumping over to the KBO following the 2019 season to sign with the Kia Tigers. Since joining Kia, Brooks has been phenomenal, anchoring their pitching staff.

As I’ve been watching and charting KBO games, I’ve gotten to see Aaron Brooks pitch three times, including his last two starts. I wrote about the first start against the Lotte Giants here and again about his July 17th start against the Doosan Bears here. Based off of these two starts and his most recent outing against the Samsung Lions, I’m taking a deep dive into Brooks as a pitcher using the pitch-by-pitch data that I’ve charted, as well as pulling in available stats from places like FanGraphs and MyKBO. So, without further ado, lets jump in and explore what makes Aaron Brooks successful.

Brooks is one of the best pitchers in the KBO, with his ERA of 2.54 ranking 5th in the league and his FIP of 3.08 ranking 3rd. His biggest strength is his amazing control of the strike zone and ability to throw strikes; Brooks has thrown a strike on 72% of the pitches I’ve seen him throw and a first-pitch strike a whopping 75% of the time, which would have beaten Max Scherzer’s MLB-leading 2019 mark of 70.3%. That’s reflected in his low BB% of 5.1% that ranks 4th in the KBO, which compensates for his average K% of 20.3% to result in the 6th best K-BB% of 15.3%.

The next best thing that Aaron Brooks does in keep the ball on the ground and limit hard contact. Brooks has a phenomenal 33/12 groundout-to-flyout ratio in games I’ve seen and has only allowed 0.30 HR/9, a mark that ranks second in the KBO. Combined with his KBO low hard-hit rate of just 11.5%, it’s clear that limiting hard contact is a priority for Brooks. He struggled to do so while pitching in the MLB, allowing a hard-hit rate of 36.8% in his 110 IP with the Orioles in 2019, an Average Exit Velocity in the 21st-percentile and xwOBA in the 14th-percentile, according to Baseball Savant.

I think that limiting flyballs and hard contact was a conscious goal of Brooks and he tailored his pitch arsenal to help him accomplish that.

Aaron Brooks has thrown four different pitches that I’ve seen, a sinker, slider, changeup, and an occasional curveball. He’s thrown his sinker about 51% of the time and mostly cut out his four seam-fastball, a pretty big change considering he threw his sinker 28% of the time and his four-seam 25% of the time in 2019. His sinker velocity has also ticked up an mph, up to 92.8 mph from the 91.8 mph he was throwing back in 2019 with the Orioles and Athletics.

Brooks backs up his fastball with his slider and changeup. He throws his slider around 24% of the time at about 86 mph, although it’s primary use is against RHH. His changeup, thrown 20% of the time and coming in around 85 mph, is Brooks’ best pitch and go-to weapon against LHH. He rarely throws his curveball, only using it 5% of the time this year after throwing it just 3.3% of the time in 2019. His curveball is more of a change of pace pitch than any sort of regular weapon.

The biggest change Brooks has made is turning almost exclusively to his sinker. I think this move has benefited him, considering the ways that his changeup and slider move relative to his sinker, which we’ll dive into more later.

Overall, Brooks’ primary approach is applicable to both right-handed hitters and left-handed hitters. He throws a steady diet of sinkers up and in the strike zone while pairing it with his changeup or slider down and away.

But an important part of analyzing an opposing pitcher is knowing what pitch he likes to through in different situations.

For each potential pitch count, I’ve pulled the number of each pitch Brooks has thrown and compiled it into this table, with green filled boxes indicating he’s likely to throw the pitch in question, red indicating that he likely won’t throw the pitch and yellow indicating some uncertainty. We’ll examine his pitch tendencies by LHH vs RHH a little more in-depth soon, but let’s take a look at his overall approach.

Aaron Brooks isn’t the most extreme fastball-heavy pitcher in the KBO (that’d likely be Chris Flexen), but his sinker is still his most used pitch (also, an interesting note is that Aaron Brooks, over the 313 pitches that I’ve charted him throwing, has not reached a 3–0 count versus any batters, another testament to his command and control). His sinker is his go-ahead pitch against hitters and the pitch he turns to when he needs a strike. He uses his changeup and slider later in the count, with his slider frequently being used in two-strike counts and his changeup being used when’s behind or even in the count.

Brooks has been excellent overall but has been great against RHH, holding them to a 0.216 batting average on the season, while LHH have hit 0.286 against him. However, he’s gotten more strikeouts (38) against lefties than he has against righties (34). A big part of that has to do with how he uses his pitches against opponents, something we’re about to dive more into.

SINKER

Aaron Brooks has turned into a sinker-heavy pitcher with the Tigers. It’s his most used pitch, throwing it 56% of the time against RHH and 48% of the time versus LHH. It’s an incredibly reliable pitch for him, and the pitch that he can throw for a strike almost whenever he wants it. He uses his sinker as a go-ahead pitch, throwing it 53% of the time in 0–0 counts, 50% of the time in 2–0 counts, and 67% of the time in 3–2 counts.

At about 93 mph, with a wicked cut towards Brooks’ arm-side, his sinker is already a really tough pitch to hit. Based off of that movement profile, Brooks uses his sinker differently against RHH than he does against LHH. It’s his go-ahead pitch against righties, with just an 11% whiff rate. As you can see on his plotted sinker locations, he throws his sinker inside against RHH, which really helps induce those groundballs and that weak contact that have been crucial to Brooks’ success.

Against LHH, with that sharp cut back towards Brooks’ arm-side, his sinker is a heavier swing-and-miss pitch, with a 23% whiff rate. Brooks accomplishes this by throwing the sinker up and ramping the velocity up to the 94–95 mph range when he’s hunting a swing-and-miss. In addition, he pairs it really well with his changeup and slider, which only boosts the deception factor. He avoids throwing it in the middle of the plate, for the most part, effectively locating for a strike on the inside edge of the plate, for a whiff up in the zone, or for a groundball away from LHH.

The sinker is Brooks’ best friend early in the count and when’s down in the count. He’ll use it to induce swings-and-misses against LHH in two-strike counts but it’s more of a called strike type of pitch against RHH. Hitters can sit sinker early and lefties should be wary of it late in counts; righties have another problem to worry about.

SLIDER

Brooks uses his slider against both RHH and LHH, throwing it 30% and 20% of the time respectively. In the 85–87 mph, Brooks doesn’t get a whole lot of horizontal break, but the lack of movement actually plays pretty well off of the arm-side run that his sinker and changeup get.

Brooks is very confident in his slider and is willing to throw it for a strike when needed, throwing it for a strike 79% of the time against righties and 78% of the time against lefties. It also does double duty against RHH, inducing a whiff rate of 27%, which is why he primarily uses it in two-strike counts, throwing it 29% of the time in 0–2 counts, 31% of the time in 1–2 counts, and 36% of the time in 2–2 counts.

Left-handed hitters don’t fare as poorly, with a whiff rate of 19% and swing at his slider the most out of any pitch he throws with a 73% swing rate. Some of that has to do with where he throws it; locating his slider in the zone is naturally going to lead to it being put in play as opposed to when he throws it inside or down. He could cut down on his slider usage to LHH, but I’d advise against it and you’ll see why when we discuss Brooks’ next pitch.

Overall, righties have to more vigilant for the slider in two-strike counts as that when Brooks uses his slider down and away for whiffs. Lefties have fared relatively well so far against his slider which he’ll usually throw when he’s ahead against lefties.

CHANGEUP

Aaron Brooks’ best pitch is his changeup against left-handed hitters. He throws it 28% of the time against lefties versus just 6% against righties, so I’ll be discussing his changeup in context against lefties. Coming in around 85 mph, just off of his slider, Brooks’ changeup has been ridiculously successful against lefties, with a strike rate of 74% and a whiff rate of 31%.

An overall whiff rate of 31% is pretty good; Patrick Corbin and Jacob deGrom had overall whiff rates of 31.8% and 31.5% last season, so having one pitch as good as those two is excellent territory. The side-to-side movement and drop off that Brooks is able to induce is remarkable and makes his changeup one of the most potent pitches I’ve seen.

Brooks locates his changeup down and away from lefties, maximizing the vertical break and arm-side run that he gets on the pitch. The combination of arm-side run and vertical drop that Brooks induces is absurd. At 86 mph, I don’t know how you’re supposed to hit a pitch that drops off of the end of the table like, especially breaking away from you.

Apparently, neither do KBO hitters. Brooks has thrown 53 changeups to lefties in the three games I’ve watched and has induced 10 groundouts on the pitch and 10 whiffs. That’s a ridiculous success rate and exactly what Brooks sets out to do against hitters.

Brooks doesn’t throw his changeup very much in two-strike counts, rather primarily using it in 0–1, 1–0, and 2–1 counts to set up the hitter. The best-case scenario is a weakly hit groundball or whiff, either resulting in an out unsettling the hitter. The downside of throwing a changeup in those counts is relatively minimal, resulting in a ball, but also setting up his sinker or slider if needed. Lefties need to be prepared to face Brooks’ changeup, but that doesn’t make it any easier to hit considering its similar shape to his sinker and the near-identical velocity with his slider.

CURVEBALL

Aaron Brooks rarely throws his curveball, only using it 8% of the time against RHH and 4% of the time against LHH at around 80 mph. It’s primarily a change of pace pitch for him and he gets a decent amount of strikes on it, with a strike rate of 86% against LHH. He’s thrown it 11% of the time in 1–1 counts which signals that he uses it to try and “steal” a pitch to get to a 1–2 count.

Hitters, on either side of the plate, don’t need to worry about facing his curveball. He uses it to steal the occasionally strike, but its usage is so sporadic it’s not worth trying to predict.

Recapping Brooks’ Approach

Against RHH, Brooks likes to lead with his sinker in the zone and slider down and away. His slider is his swing-and-miss pitch while his sinker is a very reliable strike whenever he wants it. Brooks’ main goal against righties is to induce soft contact on the ground and he’s excelled at that so far this season.

Lefties have to be wary of each of Brooks’ three primary pitches. His sinker is a strike pitch and he elevates it for a whiff when he needs it. His changeup is his best pitch, diving down and away to lefties and inducing a lot of groundouts and whiffs. Hitters should be trying to sit on his slider on the inner third of the plate.

Aaron Brooks always wants to induce weak contact and groundouts but is willing to go after swings-and-misses, especially against lefties.

*Stats from FanGraphs, myKBO.com, Baseball Savant, Sports Info Solutions, and the official KBO website*

While MLB Summer Camps are (trying to) ramp up, baseball continues across the ocean in Korea with the KBO. The action is heating up as teams approach 60 games played and tiers start to become more defined. The NC Dinos and Kiwoom Heroes are 1 and 2 in the standings as they headed into game 3 of an important series today.

The NC Dinos beat the Kiwoom Heroes 9–1 to avoid a sweep, maintaining their hold over the #1 seed in the KBO standings. Drew Rucinski led the way for the Dinos, throwing 7 shutout innings and keeping Kiwoom’s powerful bats silenced.

One of the best pitchers in the KBO, Rucinski, a 31-year-old RHP with MLB experience with the Angels, Twins, and Marlins, has allowed just 2 ER in his last 26 IP for NC. His 2.05 ERA is 3rd in the KBO, his FIP of 3.79 is 11th, his WHIP of 1.80 4th, and his LOB% of 86.5% the best in the league. I saw Rucinski’s first start in this scoreless stretch and not much changed from that June 28th outing against Doosan.

In both starts, he threw strikes around 61–64% of the time and excelled at getting ahead in the count, throwing a first-pitch strike 70% of the time against Kiwoom. Rucinski induced a lot of soft contact both times, despite his GO/FO ratio of 0.78; most of those flyouts were popped up. And, of the five hits that Kiwoom had off of him, 3 of them were softly hit infield singles that the batters managed to outrun. His Whiff % also increased, up to 33%, a phenomenal number.

A lot of that weak contact and groundball hits were a product of how he was attacking hitters. He worked up and away to LHH, except for his curveball which he threw down and in. Against RHH, he attacked lower in the zone, throwing his slider and curveball breaking away from RHH and his sinker/fastball at the bottom of the zone.

It’s an effective approach for Rucinski with the 5 different pitches that he throws. His sinker breaks arm side, averaging around 90 mph. He actually upped the sinker usage this time, throwing it 41% of the time against Kiwoom versus just 28% of the time against Doosan. With an uptick in his sinker usage, he didn’t throw as many four-seam fastballs, only throwing it 14% of the time around 90 mph as well. His overall velocity numbers were down just an mph or two and I wonder if he made the conscious decision to go with his sinker, given its greater deception/movement. Whatever it was, it worked as he induced 6 of his swinging strikes on the sinker.

But Rucinski’s best swing and miss pitch is his slider, inducing 5 whiffs on the 19 times he threw it. Coming in around 86 mph, there isn’t much side-to-side movement, but it has a tight shape and drops right as it approaches the plate. Compared with his curveball, which has a similar shape at 81 mph, but more break overall, it’s a really effective combo. His curveball induced 3 swings and misses, giving him 8 whiffs on 37 total breaking pitches.

Rucinski only threw his changeup 7% of the time and primarily outside to LHH. It came in around 84 mph, giving him another change-of-pace between all of his offspeed pitches. There was nothing notable about it and it’s not worth worrying about from a hitter’s perspective.

Rucinski likes to get ahead in the count early with his sinker/fastball then go after swings and misses with his slider/curveball combo. If he falls behind in the count, he’ll usually turn back towards his sinker, relying on its side-to-side break to help induce weak contact on the ground. His increased whiff rate looks like a result of heavier slider/curveball usage down in the zone, paired with his fastball up, especially against LHH.

The KBO has been playing games for over two months now, with most of the teams in the league approaching 60 games played. This gives us a pretty good sample size to evaluate players and trends, especially on the pitching side.

Raúl Alcántara, a 27-year-old RHP with 46.1 IP of MLB experience, has had a stellar start to his second season in the KBO, becoming the ace of the (as of July 12th) 3rd-place Doosan Bears. At 6’4’’, 220 lbs, Raúl Alcántara is one of the biggest pitchers in the KBO and takes advantage of that as the hardest thrower in the league. I’ve had the chance to see Alcántara throw 3 times this season, against the LG Twins on June 21st and against the NC Dinos on June 27th, as well as his most recent start against LG on the 9th for data collection purposes. From these three games, I have pitch location and pitch-by-pitch data, giving me just over 300 pitches from Alcántara to analyze.

The purpose of this article is to take the data that I’ve collected from watching 3 of Raúl Alcántara’s starts and paint a picture of him as a pitcher. I’m diving into what his pitch tendencies and results look like and how he attacks hitters. Using that information, we can start to build a game plan for a team or hitter who is facing Alcántara.

Raúl Alcántara has been one of the best pitchers in the KBO this season and a quick glance at the box score that I put together for him supports that; there’s a lot of green there in his season-long stats. He’s top 10 in ERA, FIP, batting average allowed, and LOB% while ranking top 5 in WHIP, BB%, and K-BB% while throwing 68% of his pitches for a strike.

The thing that stands out to me the most about Alcántara is his ability to throw and get strikes. That 68% mark is one of the highest I’ve seen in the KBO and his BB% of 3.8% is one of the lowest, speaking to his command. His overall approach is to throw in the zone and let everything else stem from there.

Another thing that stands out to me is that, despite his fastball that averages ~ 94 mph, Alcántara only has a K% of 21.9%, which is good, but not quite where I would expect given how fast he throws. His secondary pitches are his slider, around 86 mph, and his changeup, also around 86 mph. His slider is his go-to whiff pitch, as it has been since he was with the Oakland Athletics, but he just doesn’t get much movement on any of his pitches. According to his Baseball Savant page, in 2017, with the A’s, Alcántara’s vertical movement was below the MLB average on his main three pitches thanks to low spin rates. His four-seam fastball averaged a spin rate of 2144 rpm, which landed in the 27th percentile. His slider averaged about 2106 rpm, also below average. With that lack of movement, Alcántara tends to pitch a little more to contact and in the zone.

Alcántara really does pound the zone, as the location plot indicates. His strike % is also helped by the fact that he gets a lot of calls on the corners. He tends to work away from both RHH and LHH, keeping his fastball up in the zone, his slider down and away from RHH, and his changeup low to both sides of the plate.

So, we’ve identified the 3 main pitches, plus the curveball, that Alcántara throws. But when does he use each one?

Here’s the answer to that question. Of the 305 pitches I have on Alcántara, I calculated how frequently he threw each pitch in each count and this is the result. We’re going to start with the easiest one: his curveball. Alcántara rarely throws his curveball, maybe 2–3% of the time, and when he does throw it, it’s when he’s ahead in the count, like an 0–1, 0–2 count. It’s a change of pace from his other pitches and that’s about it.

His slider is his go-to swing and miss pitch (as we’ll see with its Whiff % in a little bit). Alcántara uses it in almost every single 2-strike count or when he’s ahead. His changeup isn’t used quite as much, but Alcántara primarily throws it early in the count or when he’s ahead (and usually against LHH). As expected, his fastball is his most-used pitch and the pitch he throws when he needs a strike in any hitter’s count.

Now that we’ve taken a look at his overall approach and background, let’s dive into each pitch in a little more detail.

FASTBALL

Alcántara’s primary pitch is his fastball, throwing it around 55% of the time overall. However, there is a pretty stark usage difference between RHH and LHH, with Alcántara throwing his fastball 64% of the time to righties and just 49% of the time to LHH.

He approaches hitters from both sides of the plate similarly with his fastball. Alcántara keeps his fastball elevated in the 93–94 mph range and uses the fastball as his strike pitch, with a 66% strike % vs RHH and 75% strike % vs LHH. Using his fastball up in the zone helps maximize his secondary pitches and his velocity. As you can see in the GIF above, while his fastball is not his primary swing-and-miss pitch, the ability to ramp up the velocity to 96–97 when needed lets Alcántara induce whiffs when he wants.

Alcántara frequently throws his fastball as his first pitch but stays away from it if he gets a strike on the first pitch. If the first pitch is a ball or he goes down in the count, he’s likely to go right back to the fastball until he gets a strike. His fastball usage is highest in 1–0, 2–0, 3–0, and 3–1 counts, which is when hitters should be sitting fastball up in the zone. Of course, that’s easier said than done considering that Alcántara has the ability to throw that pitch at 95+ mph for a strike.

SLIDER

Alcántara’s slider is his most-used secondary pitch (25% against RHH and 28% against LHH) and is his most dangerous pitch. There’s not a lot of sweeping side-to-side action on it (thanks to that low spin rate), but he routinely throws it in the 86–87 mph range.

Against RHH, Alcántara uses the slider down and away as a chase pitch. Against LHH, he throws it in that same spot or more in the zone for a strike (showing that variety against LHH in the GIF above). It’s effective against batters on both sides of the plate, with a Whiff % of 33% against RHH and a 36% Whiff % against LHH and resulting in a frequent strike for Alcántara. It’s clearly his most effective pitch and I’d love to see him increase its usage a little bit more to induce more swinging strikes.

Alcántara’s slider is primarily used with 2-strike counts as his put-away pitch. Lefties should expect to see the slider earlier in the count than righties should with Alcántara’s reduced fastball usage against LHH and the ability to throw his slider for a strike.

CHANGEUP

Alcántara’s changeup is interesting and its primary purpose seems to be as a change of pace pitch against LHH. Averaging 85.7 mph, his changeup gets a decent amount of arm side run, which explains the disparity of usage from LHH (20%) vs RHH (8%). As shown in the GIF above, that arm side break leads to Alcántara locating his changeup away from lefties.

Other than that, it doesn’t do much on its own besides setting up his fastball/slider combo. He throws the changeup for a strike ~ 50% of the time against both RHH and LHH while inducing 0 Whiffs in the 3 games that I charted. Alcántara really only throws his changeup early in the count and against LHHs. It’s not a pitch that I would recommend hitters sit on, which it appears they don’t, considering that lefties have a 29% swing rate and righties have a 25% swing rate on his changeup. Both his fastball and slider are way more likely to be used in higher leverage situations, rendering his changeup a moot point when game planning against Alcántara.

PUTTING IT ALL TOGETHER

Right-handed hitters should be looking for a fastball early and slider when Alcántara is ahead in the count. If Alcántara falls behind in the count, expect a heavy diet of fastballs for RHH.

Left-handed hitters should be prepared for the fastball early or when Alcántara is down in the count, but their chances of getting a slider/changeup early are much higher. If Alcántara is ahead early, 0–1, 0–2, 1–1 counts, it’s likely a slider/changeup for lefties.

Raúl Alcántara is a much simpler evaluation than his teammate Chris Flexen is. Flexen throws 4 different pitches, with their usage varying a lot based off of the lefty/righty matchup. Alcántara is a 3-pitch pitcher who really only throws 2 pitches against righties with a little more variety against lefties, but his slider is still his go-to swing-and-miss pitch. Despite less deception and trickery on Raúl Alcántara’s part, he still throws 94+ when he wants to and that’s something that a gameplan can’t account for; hitters can either hit it or they can’t.

*Stats from myKBO.com, FanGraphs.com, Baseball Savant and data I pulled from the KBO on ESPN broadcasts*

The Korean Baseball Organization was the first professional baseball league to get started this year after the disruptions that COVID-19 has caused across the world. As in years past, many former MLB players, either towards the end of their playing days or looking to improve and return to MLB, are playing in the KBO. One of those players, Chris Flexen is in the latter category.

Flexen is a 26-year-old who was drafted back in 2012 out of high school by the New York Mets in the 14th round. Standing at 6’3”, 249 lbs, Flexen poses an intimidating figure on the mound in Korea. Flexen is in the midst of his first season in the KBO, pitching for the Doosan Bears and has been one of the better pitchers in the KBO. As I have been watching and analyzing KBO pitching matchups, I’ve gotten to see Flexen 3 times over the last month and a half, on May 31st against the Lotte Giants, dominating against the SK Wyverns on June 23rd, and against the NC Dinos on June 28th. I have pitch-by-pitch data from all 3 starts and pitch locations from the last two starts.

The purpose of this article is to examine what makes Flexen tick on the mound and how I think hitters should approach a matchup against Chris Flexen based off of my observations from his previous starts.

Chris Flexen has had a couple of rough starts recently that ballooned his ERA up to 4.18, but we can tell he’s a better pitcher than his ERA indicates. His FIP of 3.54 profiles much better relative to the rest of the league and is much more representative of how Flexen has pitched thus far. The unlucky patch that he’s going through has been spurred in large part by his BABIP of 0.325, which is one of the worst among qualified amongst KBO pitchers.

Advanced defensive stats are hard to come by for the KBO, but we can approximate. Of Doosan’s 4 qualified pitchers, both Flexen and Young-ha Lee have FIPs that are at least 0.60 points better than their ERA. Hee-kwan Yoo’s FIP and ERA are about even while Raúl Alcántara’s ERA is about 0.42 points better than his FIP, thanks to his much lower BB% rate compared to the others. To me, this indicates that the Doosan defense is about average, likely accounting for some of Flexen’s higher BABIP as well as general poor luck.

Yet, we can’t let him off the hook too easily because he has struggled with walks this season. He’s walked 7.9% of batters faced, ranking 27th in the KBO. A lot of that has to do with only throwing a strike 63% of the time in the games I’ve seen and a first-pitch strike just 54% of the time, which is definitely below average. After he faced Lotte, I speculated that his control issues may be in part spurred by an inconsistent release point thanks to MLB data on his Baseball Savant page. Unfortunately, since there’s no KBO equivalent of the publicly available data that Baseball Savant has, that remains speculation.

Flexen throws 4 different pitches, ranging from the mid-90s on his fastball down to mid-70s on his curveball. His fastball comes in around 92 mph and is his most heavily utilized pitch. His go-to secondary pitch is his slider, coming in around 86 mph. His changeup, averaging 81 mph is primarily a situational pitch against left-handed hitters (LHH) while his curveball, at around 75 mph, serves the same purpose against right-handed hitters (RHH).

His approach against LHH and RHH is pretty similar in broad terms. Flexen works away from both lefties and righties while also using the bottom of the zone as a place to locate his off-speed pitches for swings and misses. He has been an effective strikeout guy this season, with a K% of 21.3% that ranks 12th in the KBO and a Whiff % of 29.7% that is better than what a lot of pitchers in the KBO have posted when I’ve charted games.

So, Chris Flexen throws 4 pitches. But, as a hitter, you really want to know WHICH pitch he’s going to throw WHEN.

For each count, I’ve pulled the number of each pitch he’s thrown and compiled it into this table, with green filled boxes indicating he’s likely to throw the pitch in question, red indicating that he likely won’t throw the pitch and yellow indicating some uncertainty. We’ll examine his pitch tendencies by LHH vs RHH a little more in-depth soon, but let’s take a look at his overall approach.

An important thing to note here is that Flexen throws his fastball A LOT, throwing it 59% of the time in the 3 games I’ve seen him (He threw it 58% of the time in 2019 with the Mets, while also throwing a sinker, which I have not seen at all). With that in mind, if you can only bet on one pitch coming, bet fastball. His fastball is his go-ahead pitch, the pitch he throws when he needs a strike, as evidenced by its heavy usage in 2–0, 2–1, 3–0, 3–1, and 3–2 counts.

Once you get away from those counts though, things start to get a little more ambiguous. Each one of his secondary pitches has swing and miss capability, while he also shows confidence in his ability to throw his slider for a strike early in the count. His changeup’s usage is the most notable, coming almost exclusively in 2-strike counts and, as we’ll see later, against LHH. His curveball has a similar usage, being used most frequently with 1 or 2 strikes as a chase pitch against RHH.

Keeping in mind WHEN he uses each pitch, let’s move onto examining each pitch in more detail.

FASTBALL

Chris Flexen’s primary pitch is his 4-seam fastball. Over his past few seasons in MLB, he also displayed a sinker, but its usage dropped from 42% in 2017 down to 3% in 2019 and it appears that he’s phased it out of his arsenal in the KBO. He throws his fastball equally to both LHH and RHH, at 58–59% of the time, averaging around 92 mph with the ability to ramp up to 94/95 mph when he wants to. That velocity has always been Flexen’s calling card, averaging 94–95 mph with the Mets as a reliever, and it separates him from other pitchers in the KBO save for one or two other foreign-born players.

Flexen likes to locate his fastball away from both LHH and RHH and in the upper-to-mid portion of the zone. Doing so helps maximize the velocity of his four-seamer, especially when he throws it off of his slider or curveball. He does have a tendency to try and work around the edges of the zone with his fastball, which is why it has a Strike % of 62%, which is a tad below where you might like a guy to be with his primary pitch.

That tendency likely has to do with the way his fastball moves; with the Mets, Flexen’s velocity was in the 71st percentile, but his spin rate was in the 23rd percentile, leading to below-average movement. That’s very clearly reflected in his Whiff % of 17% against RHH and what informs his approach. His Whiff % is a lot higher against LHH, but it’s a much smaller sample, but again indicates how his velocity gives him a tool to fall back on even with less movement.

Hitters should be sitting fastball early in the count. Flexen likes to try and get ahead by throwing a fastball in the zone and away, which in the KBO works as hitters tend to be extremely patient and rarely swing on the first pitch. If he gets ahead on the count or a Whiff on his fastball, he’ll return to it if the hitter fouls off his other pitches or he can’t locate something. Almost every time I’ve seen Flexen give up a hit on his fastball, it’s been down the middle half of the plate, which he only attacks early in the at-bat.

SLIDER

I really like Flexen’s slider as his secondary pitch. There’s not much side-to-side action, but it looks very similar to his fastball out of his hand and then breaks pretty sharply before getting to the plate. Coming in at 86 mph, he again shows the ability to ramp it up to 88–89 mph when needed which is a hard pitch to hit.

The slider is a pitch he uses more against RHH, throwing it away from them, either in the down and away corner of the zone or down further as a swing and miss pitch. Against LHH, he’s utilized the slider as another strike pitch, evidenced by his 82% Strike % on the slider against LHH. It’s a pretty good Whiff pitch, with a 30% Whiff rate against RHH and 29% against LHH (in just 11 pitches though), and it really helps him set up his other offerings. He uses one of two ways, either as that chase pitch in 0–2 counts or to get a strike early on.

Right-handed hitters should be looking out for the slider as a Whiff pitch when the count is 0–2 or Flexen is ahead. Otherwise, he does like to locate it in the zone for a strike if he’s not throwing his fastball early in the count. He rarely ever throws the slider once there are more than 2 balls, partly due to the vertical drop that can make it a risk to be called a ball.

CURVEBALL

Flexen’s curveball is an intriguing pitch that he primarily uses against RHH. Left-handed hitters should not be focused on this pitch and, as such, I will be discussing its qualities for right-handed hitters.

Flexen uses his curveball as a swing-and-miss pitch against RHH. He locates it down in the zone, only getting a strike 43% of the time, but a 36% Whiff rate. He has to locate it down and, in the dirt, because it’s a very distinctive pitch with a huge amount of vertical drop and a big hump. As you can see in the GIF above, he gets a few swings on curveballs at or below the knee, but when he locates in the zone, the hitters barely even flinch.

Chris Flexen has primarily thrown his curveball in 0–1, 1–1, and 1–2 counts for a good reason. To get into those counts, he’s almost always thrown a fastball and/or slider combo to get into that count and his curveball, down in the zone, can come out of that same tunnel. That’s when his curveball becomes really hard to hit. But the distinctiveness of its shape gives hitters an easy signal to decipher if he tries to throw it in the zone; that’s how he gave up an HR once on his curveball, by leaving it up in the zone after its full breaking motion, making it easy to identify.

His curveball is best utilized pounding below the zone as a chase pitch and that’s when hitters need to look out for it. If he induces a whiff on his fastball or slider as he gets ahead in the count, the curveball is very likely to be his put-away pitch with its similar path early in its movement towards the hitter. LHH shouldn’t be worried about facing a curveball from Flexen unless it’s just as a change of pace early in the count.

CHANGEUP

Much like his curveball, Flexen’s changeup is a specialized pitch, but against LHH whereas his curveball is a righty-on-righty weapon with a 19% usage against LHH vs just 5% against RHH.

Flexen’s changeup is a weapon against LHH, averaging about 81 mph, giving him an offering between his slider and curveball. He’s thrown it for a strike 81% of the time, which includes the 6 Whiffs on 12 swings he’s induced from lefties on the pitch. It’s a lefty weapon due in part to the arm side run that he’s able to put on it, drifting away from lefties at the plate. As shown in the GIF above, throwing it down in the zone has been an effective plan of attack for Flexen. He primarily throws the changeup in 2 strike situations which makes sense given its effectiveness as both a swing-and-miss pitch and being able to locate in the zone.

In an 0–2 or 1–2, Flexen has been more likely to throw the changeup down in the zone being ahead in the count with a little bit of a cushion while in 2–2 count, he elevates the pitch into the lower half of the zone.

Putting It All Together

Now that we’ve taken an in-depth look at every pitch that Flexen throws and when he throws it, how should hitters be attacking him?

Overall, Flexen works away from LHH and RHH, while also working down against righties with his slider and curveball. His fastball/slider are his strike pitches while his curveball (RHH) and changeup (LHH) are his put-away pitches.

Early in the count, hitters should be sitting fastball. It’s his most frequent pitch and the pitch that he can confidently locate in the zone. I’d recommend going to the plate planning on attacking a potential first-pitch fastball; however, KBO customs are different and their patience leads to infrequent swings on the first pitch.

After the initial pitch or two, Flexen frequently throws his slider. If he’s down in the count 1–0 or 2–0 and needs to throw a non-fastball, he’ll throw the slider in the zone. If he’s ahead, 0–2, 1–1, he’ll throw it low and try to induce a Whiff.

If he gets to a 2-strike count, that’s when things start to get interesting. For LHH, they should be wary of a changeup, either in the dirt if it’s 0–2/1–2 or in the lower half of the zone when it’s 2–2. Right-handed hitters are looking out for a curveball in 0–2/1–2 counts. The curveball comes out of the same slot as his slider/fastball, making it hard to pick up on when he throws it low in the zone.

If he falls behind in the count, expect a heavy diet of fastballs in the zone. Once he’s down 2–0, he’ll focus on the fastball, rarely throwing anything else except for the occasional slider.

That is how you attack Chris Flexen when he’s pitching against you.

*Stats from myKBO.com, FanGraphs.com, Baseball Savant, and data I pulled from KBO on ESPN broadcasts*

Major League Baseball may be returning within the next month, but in South Korea, the KBO keeps on playing. ESPN continues to broadcast its games and is helping to fill the void that the MLB labor dispute has created.

Behind the strength of a 2-run outing from Chris Flexen and an 8-run performance from their offense, the Doosan Bears defeated the SK Wyverns easily by a score of 8–2. This is the 2nd time that I’ve seen Chris Flexen pitch this season for the Bears and he pitched much better against SK than he did against the Lotte Giants the first time around, despite allowing more earned runs.

Flexen, a 25-year-old RHP, has some MLB experience from his time with the New York Mets in 2019, throwing 13.2 IP in New York before jumping to the KBO. He’s been fairly successful this season with the Bears, posting a 3.29 ERA and a 3.77 FIP. He striking out 7.68 batters per 9 IP, but walks have been an issue as Flexen has issued 3.51 BB/9 resulting in a K/BB ratio that is in the bottom 25% of the KBO.

In the first start of Flexen’s that I saw, back at the end of May, he pitched a lot to contact, trying to induce weak contact, and it worked, with 10 groundouts vs 3 flyouts and 2 strikeouts. But he also struggled with his command, walking 5 batters and throwing a ball 43% of the time. Against the Wyverns though, he shifted, throwing 71% of his pitches for a strike and inducing an astounding 39.65% Whiff Rate. That’s exactly what I want to see from Flexen.

Flexen, a former MLBer, has velocity that is above average for the KBO. His fastball averaged nearly 92 mph against the Wyverns and he routinely touched 93–94 mph. His slider came in around 87 mph and he was consistently commanding it for a strike or chase pitch below the zone. Flexen didn’t really throw his 12–6 curveball, only using it 11% of the time, but it averaged around 77 mph and spins pretty well, at 2766 rpm in 2019 with the Mets, within the 84th percentile, and a ton of vertical drop. Much like his slider, Flexen located the curveball for a strike or below the zone, inducing 3 Whiffs on it.

His changeup is absolutely a situational pitch against left-handed hitters (LHH), but it was devastating against the Bears with his arm-side run. He threw 10 changeups, with 7 of them to LHH for 5 Whiffs, with another Whiff to an RHH. Of course, it’s an extremely small sample size, but that’s quite a weapon. The changeup comes in around 81 mph and, according to StatCast in 2019, had a spin rate of 1267 rpm, the 9th lowest rpm on a changeup in 2019.

The walks and control issues have been a problem for Flexen his entire career, but against the Bears, he attacked the strike zone relentlessly and walked 0 batters. A potential concern that I identified after his last start was his erratic release point, with all of his pitches being released from different points. Flexen is a big pitcher, standing 6’3” and releases the ball with an over the top delivery. With the side-to-side and up-and-down changes in his release point, it made sense that it could still be a pervasive issue that was hindering his ability to throw strikes. Of course, since there’s no (publicly available) StatCast-type tracking data, it’s really hard to know whether anything has changed for Flexen in that area.

However, his StatCast location plots were all over the place for all of his strikes, notably missing to the sides with his fastball. With the locations from last night, we can see that Flexen was really contained in the strike zone and his overall plot is pretty straight, only trailing into the LHH batter’s box low in the zone, where he threw his slider and curveball that drift glove side. Flexen placed 53% of his pitches in the strike zone, above his 43.4% mark in the majors. I’d need to see more starts to be sure, but it looks like Flexen may have fixed some of his command issues. If he has, I could definitely see a return to the MLB in the next few years, especially as a reliever, given Flexen’s velocity and slider/changeup combo.

For now, while Flexen is in the KBO, expect a heavy diet of fastballs up in the zone. His changeup is his out-pitch against LHH and he has displayed the ability to throw his slider/curveball both in the zone and below the zone for a swing and miss pitch. Throws hard with a good mix of movement and deception depending on the situation. I expect starts like this to be much more the norm for Flexen heading forward in the KBO.