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.
The NC Dinos finished off an important series against the Doosan Bears by winning 2 games out of 3, taking the series finale by a score of 5–0 thanks to 7 sterling innings by Drew Rucinski who outpitched Chris Flexen. The two best offenses in the KBO faced off against two of the best pitchers and the pitchers came out on top.
Drew Rucinski, a 31-year-old RHP, is in his second season with the NC Dinos after accruing 54 IP in the MLB with the Angels, Twins, and Marlins. Heading into this game, he’s been one of the best pitchers in the KBO, posting a 2.38 ERA, 3rd in the league, with 8.53 K/9, and would be the ace of the Dinos’ staff if not for the meteoric rise of Koo Chang-mo. Some of his success has been luck driven, as his 3.81 FIP indicates, but the Dinos seem to have an above-average defense; Rucinski, Mike Wright, and Koo Chang-moo, their inning leaders, all have ERAs that are 1+ runs better than their FIPs.
But that shouldn’t take away from how well that Rucinski has pitched this season and he continued that success against Doosan, the KBO’s second-best offense (behind the Dinos). Over 7 IP, Drew Rucinski was ruthlessly efficient, topping 15 pitches in an inning twice, in the 1st and in the 5th when he ran into trouble. He allowed a mix of hits and walks, but kept it under control and stranded every runner who reached base, which he’s been the best in the KBO at doing thus far, with his 85.1% LOB% ranking #1 entering this matchup.
Rucinski displayed 5 pitches against the Bears and used each in specific ways. He threw two types of fastballs, using a 4-seam about 34% of the time that averaged around 92.5 mph. He paired that with a sinker that came in at 91.4 mph when he threw it, 28% of the time. He was overall fastball-heavy, with the 4-seam/sinker combo accounting for 62% of his pitches. Off of that, he primarily used his slider as a big change of pace/swinging strike pitching, throwing it 18% of the time around 86.5 mph, with a lot of vertical drop and no side-to-side sweeping movement. An interesting note on his slider is that in 2018, StatCast tracked Rucinski’s slider at 1076 rpm, which was by far the lowest spin rate on a slider from 2018–2019, causing some of that extreme vertical drop.
Overall, Rucinski’s not a guy with a lot of spin, with a fastball spin that ranked in the 5th percentile and a curveball spin that was in the 17th percentile. Speaking of the curveball, the only real difference between it and his slider was the velocity, with the curveball coming in around 80 mph with just a little bit more vertical break than the slider. It’s not a typical 12–6 curve (like we’ll see Chris Flexen sport), but the similarity to the slider makes it an interesting secondary pitch.
Throughout the game, Rucinski used each of his pitches in certain locations, pairing them together well to get 6 Ks and a 28% Whiff rate. His fastball attacked the zone and was a key part of his 65% strike rate and 68% first-pitch strike rate. He induced 4 whiffs on the fastball, with all 4 coming on ramped up velocity right after a sinker or slider; of the 5 times he induced a whiff on the sinker or slider, the next pitch was a fastball at 93+ mph 3 times, especially when it was the same batter at the plate.
He worked the sinker towards his arm side, diving away from left-handed hitters (LHH), choosing to use that more frequently than the changeup which is a typical out pitch against LHH. That’s a decision I support considering the LHH-heavy nature of the Doosan lineup and the above-average velocity that Rucinski sports for the KBO.
Out of all of his pitches, his curveball/slider combination was the most potent. He threw them a combined 29 times, inducing 7 Whiffs (4 on the curve and 3 on the slider). This is where similar shapes at different speeds came to play effectively. Rucinski primarily located his slider inside against LHH, while the curveball worked more up and down in the zone. His slider started in the same plane as his 4-seam/sinker but dropped sharply as it reached the hitter, occasionally producing some cut action when he pumped it up to 87–88 mph. The curveball had a much softer shape, breaking the whole way to the plate. The variation really seemed to mess with the hitters’ timing and helped Rucinski be effective, especially inducing weaker contact.
Despite allowing 9 flyouts versus 7 groundouts, the Bears did not hit Rucinski very hard, scoring 0 extra-base hits against him. He’s consistently induced soft contact this season; according to Sports Info Solutions, Rucinski ranked 7th in the KBO among pitchers with 100+ ABs in most soft contact allowed at 19%.
Mixing and matching his pitches in combinations that mess with the timing of opposing hitters has been a big key for Rucinski’s success this season. If hitters’ whiff on a non-fastball, they should be prepared for the next pitch to be a fastball up in the zone, pushing 93–94 mph. I recommend trying to avoid getting jammed on a slider or extending too far on a sinker that drifts out of the zone. Rucinski’s pitches have a lot of contradictory movement which makes it really hard to sit on one offering in particular and he doesn’t make many mistakes.
Chris Flexen on the other hand made one mistake and paid dearly for it, allowing all 3 of his runs on an HR in the 5th that came off of a curveball that hung at the top of the strike zone for a second too long. This marks the third time I’ve seen Flexen this season and, while he didn’t dominate the way he did versus the SK Wyverns, he pitched very similarly giving me little cause for concern over one HR and mistake.
Flexen entered this game with a 3.26 ERA and 3.41 FIP with an 8.23 K/9 mark, some of the best numbers in the KBO. Against NC, a much better offense than SK, Chris allowed 3 runs on the aforementioned HR, while scattering the rest of the 7 hits over 5 IP. He struck out 7 batters and induced more groundouts than flyouts.
Flexen continues to sport a strong 4-pitch arsenal. His fastball, which he threw around 58% of the time, comes in around 92 mph. He continued to use his slider as his best secondary pitch, throwing it around 18% of the time at about 86 mph. He continued to use his changeup sparingly against LHH, but it averaged around 81 mph, with the biggest arsenal change from a week ago was the increased usage of his 12–6 curveball, throwing it 15% of the time at 76 mph against the Dinos.
Flexen, who stands at 6’3” and throws with a pretty high arm slot, works up-and-down. His slider breaks down rather than glove side and he threw his 12–6 curveball anywhere in the zone. The curveball is very distinctive, with a big hump, and hitters usually lay off of it. But Flexen increased its usage against NC because his changeup, a phenomenal out pitch against SK’s LHH, was not effective. His slider’s effectiveness also dropped off a little, but he continued to locate the slider down and away from RHH as needed. Unfortunately, with that distinctive hump, hitters were able to adjust to the curveball and, on the HR that Flexen allowed to Kwon Hee-dong, it looked like Kwon was sitting curveball having fought off a slider and pair of fastballs earlier in the at-bat. I’m not a huge fan of using the curveball, despite the above-average spin that Flexen gets (84th percentile curveball spin during 2019) that much because of how distinctive it is. Once he regains his changeup’s top form, I expect him to use the curveball less.
Not having control over his changeup really hurt Flexen. He never throws it very much, but it’s very effective in short bursts and against LHH. His command overall slipped against NC as he failed to get the calls that he needed on the corners with his fastball and struggled to get ahead in the count early, only throwing a first-pitch strike 48% of the time. His whiff rate, which was an absurd 39% against SK came back down to earth as Flexen induced just a 22% Whiff rate, most of that coming on his fastball he when ramped up the velocity and stuck it on the corner successfully. Overall, no trends presented themselves on the pitch sequencing of his swinging strikes since they were scattered pretty well over the outing.
Hitters should be looking for a fastball up in the zone or waiting on that distinctive curveball to make an appearance. He throws both his slider and curveball in the zone and as chase pitches out of the same tunnel as his fastball. The changeup is his out-pitch against LHH.
This was a tougher outing for Flexen thanks to his lack of confidence in the changeup, but, beyond one mistake, he remained effective for Doosan. He’s only gotten better as the season has continued and this will be a small blip on the radar in a few weeks.
*Stats from FanGraphs, Sports Info Solutions, myKBO.com, and Baseball Savant*