Let’s start this off the way any baseball article should: By talking about a player who is otherwise irrelevant to the rest of the article for the sake of a metaphor. Picture Bobby Witt Jr. taking a lead off the base. The pitcher begins his stretch and Witt takes off, the catcher throws and Witt slides into the bag. Do you think he stole the base successfully? If you guessed yes, as you should have, you’d have a 72.1% chance of being right, that was Witt’s success rate this season. Keep that number in mind when I tell you that Jack Kochanowicz threw his sinker 72.4% of the time this season. Pulling from the samples, you have a better chance of a random Kochanowicz pitch being a sinker, than a Witt steal attempt being successful.
The only other starter who has a singular pitch he throws more than 60% of the time is Ben Brown with his fastball at 62.7%, which seems measly in comparison. Generally, starters just don’t do this. Relievers can get away with it because they don’t have to go through the order multiple times, and even if a hitter is expecting a guy like Emmanuel Clase to throw his cutter, they generally have better stuff than starters anyway.
The important question to ask is whether or not this strategy is working, or can work, for Kochanowicz. No. The answer is no. His 3.99 ERA looks nice but his underlying numbers are not good. Due to the pitch he throws so often being a sinker, his K% is an appallingly low 9.4%. There hasn’t been a pitcher with a K% that low across as many innings as Kochanowicz threw this season since Blaine Boyer in 2016. Even if he were managing contact as well as he was attempting to, getting punchouts so sparsely is a problem. Not all is lost though. Kochanowicz does have other pitches, good pitches even. His command of them could use work, but that’s true of most rookie pitchers.
The Arsenal
As established, Kochanowicz throws his sinker a lot. While he needs to reduce its usage, it is at least a very good foundation for the rest of his arsenal. Taller pitchers have a built-in advantage for their sinkers, as they will by default tend to have higher release points. This creates a steeper angle for the pitch, which leads to more ground balls.
At 6’7”, 228 lbs, he’s got the same listed measurements as fellow L.A. athlete Kawhi Leonard. So while his release height is around the league average, he does it with a 29° arm angle at release, which is lower than average. This leads to his fastball’s spin direction being lower down the axis, giving it less rise and more run. Adding to this is his ability to impart seam-shifted wake on his sinker, turning it into a bowling ball of a pitch that hitters struggle to get under, even when they’re expecting it. There wasn’t a single sinker in the major leagues this year with less iVB at a higher release than Kochanowicz’s. He also throws it in the zone aggressively, nearly 60% of the time, which contributes to his low walk rate. This makes him the ultimate high-event pitcher, for better or worse. So while it may not be worthy of being thrown at the rate he’s been using it, it’s a strong base for him to work off of.
His curveball moves more like a slider but its spin activity and classification lead me to believe he’s using a curveball/sweeper grip for it. Given his supination bias and ability to get high spin rates on the breaking ball it’s a bit surprising he doesn’t have something sweepier as his primary breaking ball. Maybe it’s something that could be achieved with a different grip. Regardless, as it stands it’s a perfectly fine breaking ball, with enough sweep, power, and depth to miss bats if he could stop throwing it in bad spots. His ability to zone it is impressive but he isn’t getting called strikes because hitters are in permanent swing mode expecting him to throw a sinker in the zone. After all, that’s what he usually does. The lack of whiffs is likely due to bad locations, something I expect him to clean up with time. It’s a good breaking ball. He could probably improve upon it from a stuff perspective, but he may not need to.
Kochanowicz’s 4-seam has to potential to work by way of it not being his sinker and that surprising hitters. I’ve covered pitchers with this sort of fastball combo before. In a vacuum, his 4-seam has terrible movement. But he repeats his arm action reasonably well, and they spin on a similar axis with substantial differences in vertical movement, so he can miss some bats with it. It should by no means become his primary fastball, but he could afford to work it in a bit more, especially above the zone.
Kochanowicz’s changeup is similar to a lot of changeups you see out of heavy SSW sinker guys. It has the potential to function because it looks like his fastball out of the hand with its spin axis but its movement is so similar to the sinker that it will have to function solely on deception and velocity separation, as well as his command of it, the latter of which has appeared questionable in the small sample of them he’s thrown. Other pitchers with similar changeups have made it work, so I’m not ruling it out for him. It’s tricky because what makes his sinker great winds up also being what holds his changeup back a bit. He could always try a kick change, which would probably get screwball movement given his arm slot and current spin direction for his changeup, but also suggesting that pitch for every pitcher would be lazy on my part.
The Path Forward
More than anything, Kochanowicz needs to start working his other pitches in. Iffy control of them or not, he cannot continue to be this predictable for hitters. He would also benefit from adding to his arsenal, but we’re working from scratch here. Normally I would suggest adding a cutter as a bridge pitch between his curve and his sinker, and I still will, but he needs to use them in a way that would be aided by the inclusion of a bridge pitch first. Something horizontally neutral could help open up his arsenal a bit once he starts varying his pitches. I also wouldn’t mind seeing him experiment with a different breaking ball that makes better use of his traits. I’m convinced he could throw something with more sweep, but I wouldn’t mark that as a priority.
Kochanowicz is a talented pitcher. By his fastball alone he’s got a lot going for him but his other pitches are decent too, he just doesn’t use them enough. He’s not as much of a one-pitch guy as his usage would lead you to believe. He’s very raw as a pitcher still. As the Angels have been prone to do in recent years, he was pushed very aggressively through the ranks regardless of his actual readiness.
This season was the first time he finished with a better-than-average ERA in his pro career. It’s important to remember that traits are more important than stats when evaluating pitching prospects. That said, those numbers also serve as more evidence that Kochanowicz was punching above his weight class in the majors this year. His being able to scrape by, even with some luck, was impressive.
This one is going to require substantial patience. I would not necessarily expect Kochanowicz’s real breakout to come next season. He has a long way to go to develop his secondaries and sequence them better. He’s such an interesting pitcher that I can’t help but be interested in what he does next. It’s more than just novelty though, his sinker is enough to project potential for him, he just needs to take the steps to reach it.