The Kiwoom Heroes are sitting in second place in the KBO behind the NC Dinos. With about 60 games left in their season and a lead of 5 games over the current fifth-seed, the Kia Tigers, the Heroes are in an excellent position as the season heads towards the playoffs. When the playoffs come, Kiwoom is likely to see their first action in a five-game series against whoever wins out below them, unless they can catch the NC Dinos, in which case they’d immediately jump to the Korean Series, the equivalent of the World Series for the KBO.
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.
| Month | IP | ERA | H/9 | HR/9 | K/9 | BB/9 |
| August | 12.0 | 1.50 | 6.0 | 0.8 | 8.2 | 3.8 |
| July | 8.1 | 16.67 | 17.8 | 3.3 | 7.8 | 5.6 |
| June | 29.0 | 1.86 | 8.7 | 0.0 | 5.0 | 2.8 |
| May | 22.3 | 8.07 | 11.7 | 2.0 | 6.5 | 4.0 |
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.
| BiP | Soft% | Medium% | Hard% | Strike% | Whiff% | CS% | Swing% | GO/FO | |
| Aug | 30 | 20.0 | 30.0 | 50.0 | 62.8 | 27.4 | 20.3 | 42.4 | 3.40 |
| July | 34 | 23.5 | 38.2 | 38.2 | 63.4 | 18.5 | 19.9 | 43.5 | 1.43 |
| June | 17 | 23.5 | 41.2 | 35.3 | 71.3 | 31.2 | 16.1 | 55.2 | 1.40 |
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.
| Month | 4-Seam | FF% | Changeup | CH% | Slider | SL% | Curveball | CU% |
| August | 87.3 | 44.8 | 78.5 | 14.0 | 81.1 | 27.3 | 75.0 | 14.0 |
| July | 86.4 | 49.5 | 77.8 | 16.1 | 79.0 | 18.8 | 73.0 | 15.6 |
| June | 86.3 | 43.7 | 78.4 | 9.2 | 79.2 | 27.6 | 73.3 | 19.5 |
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.
| Month | Pitches | Heart% | Shadow% | Chase% | Waste% |
| August | 172 | 12.8 | 51.7 | 27.9 | 7.6 |
| July | 186 | 15.6 | 48.4 | 29.0 | 7.0 |
| June | 86 | 27.9 | 44.2 | 23.3 | 4.7 |
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.
| Month | Pitches | Strike% | Whiff% | CS% | Swing% | Contact% | GO/FO |
| August | 77 | 70.1 | 6.1 | 27.3 | 42.9 | 93.9 | 1.25 |
| July | 92 | 65.2 | 4.8 | 19.6 | 45.7 | 95.2 | 1.50 |
| June | 38 | 84.2 | 25.0 | 21.1 | 63.2 | 75.0 | 1.00 |
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.
| Month | Pitches | Strike% | Whiff% | CS% | Swing% | Contact% | GO/FO |
| August | 24 | 79.2 | 46.7 | 16.7 | 62.5 | 53.3 | 5/0 |
| July | 30 | 56.7 | 37.5 | 3.3 | 53.3 | 62.5 | 0.67 |
| June | 8 | 50.0 | 33.3 | 12.5 | 37.5 | 66.7 | 1/0 |
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.
| Month | Pitches | Strike% | Whiff% | CS% | Swing% | Contact% | GO/FO |
| August | 47 | 57.4 | 45.5 | 10.6 | 46.8 | 54.5 | 6./.0 |
| July | 35 | 71.4 | 37.5 | 25.7 | 45.7 | 62.5 | 2./0 |
| June | 24 | 75.0 | 43.8 | 8.3 | 66.7 | 56.2 | 2.00 |
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.