Karinchak had Glasnow’s Curveball… and Said No

In his abbreviated rookie year, James Karinchak dominated out of the Cleveland Indians’ bullpen. He was a little wild, but striking out 48.6% of batters more than made up for it. The root of his success? One of the best four-seam fastballs in the game. His combination of velocity and backspin translated to his fastball having the least drop in the MLB. Its corresponding 39% whiff rate would make Gerrit Cole blush.

The point of that opening paragraph: Establish Karinchak’s fastball is crazy. Nobody can produce the movement he does. Despite this, Karinchak throws nearly an equal proportion of curveballs. He throws it hard and its success rivals his fastball’s, but the movement profile is odd. It drops 1.4 inches less and sweeps 5.5 inches less than expected. While savant’s pitch movement section gives it disapproving shades of blue, the pitch’s shape was intentional.

In his five game 2019 stint, Karinchak featured a hammer curveball as his secondary offering. The type of velocity and topspin he was generating was no fluke. He had Tyler Glasnow’s curveball yet chose to move away from it in 2020. Without sufficient sample sizes, it is hard to outright say this was a smart move. However, I do think it is worth discussing reasons such a change would make sense.

Command and Usage

The first thought that came to mind was command. That level of velocity and drop produces plenty of whiffs in the dirt, but can be somewhat redundant when throwing a ‘get me over’ curveball. Sure, the movement makes the hitter less likely to swing, but may not be worth the extra difficulty to command. That tradeoff is a calculated one.

Running with the Glasnow comparison, that curve has taken him a long way. Had it not been for a forearm strain in 2019, he may well have won the AL Cy Young as a two-pitch pitcher. As effective as it has been for him, Glasnow almost never uses it when behind in the count. Instead he leans on his elite fastball to pound the zone – throwing it over 85% of the time when behind.

That is a choice Glasnow has made. He knows he can get away with pounding the zone with his fastball and therefore has the leniency to chase a more whiff-friendly curveball. Karinchak goes for a more balanced approach. Both in terms of pitch percentage and zone percentage – his curveball is much closer to his fastball than Glasnow (see below). Even when behind in the count, Karinchak maintains a nearly equal proportion of fastball and offspeed offerings.

The question of whose approach is better is outside the scope of this article. Rather, my point is that Karinchak needs his curveball to be able to land in the zone. Not only that, he needs to be able to consistently locate it on the fringes of the strike zone. With this extra leverage being put on its command, dialing back the topspin just might make sense for him. After all – no matter the secondary pitch he chooses – it has the benefit of playing off arguably the most electric fastball in the game.


Speaking of playing off the fastball, let us discuss pitch tunneling. If you are unfamiliar, check out this video I made a while back introducing the concept. With velocity being held constant, movement is once again a tradeoff. A larger movement gap means more whiffs when the hitter guesses wrong, but a higher likelihood of the hitter discerning the pitch type early in the pitch’s flight. Increased velocity provides increased leniency.

Using both his fastball and curveball in the zone, it makes intuitive sense for Karinchak to pursue a narrower movement gap between the two. If the gap is too large, hitters can quickly tell what pitch it will be based on its initial trajectory. Bauer calls this concept early identification. As a hitter, you may end up swinging at a few eye-level fastballs or one-hop curveballs, but you will usually be right guessing on pitches that leave a neutral tunnel early. The sample sizes are still small, but this explains why Karinchak avoids the bottom of the zone with his fastballs: The plane required to get there gives hitters an early indication it is a fastball. The same concept applies to his curveballs high in the zone. His electric stuff lets him get away with more than most, but play with fire enough and you will get burned.

Another sample size warning, but his curveball had the highest whiff rate in the MLB last year. Pointing at positive results exclaiming ‘look it worked’ is no route to perfection, just confirmation bias. However, I think it provides an indication of a direction to look. The benefits of increased tunneling could be outweighing the effects of a reduced movement gap when hitters are fooled.

Speaking to this, I will finally discuss the oddity of the first graph in this article. Initially I only discussed vertical movement simply because the topic of horizontal movement is so juicy. In 2020, Karinchak’s curveball had arm-side movement. In a way, he throws a 12-6 screwball. This is not unprecedented, Drew Smyly throws a similar screwy offering, but needless to say it is quite absurd. Akin to his Glasnow-like 2019 curveball, it has a movement profile few can replicate. Theoretically, the arm side further aids tunneling. Granted, holding a vertical plane is more important when it comes to tunneling. Still worth mentioning.

Going Forward

Results suggest the reduced-drop curveball was a good move in 2020. Dare I suggest he push it further? The analysis that follows is beyond questionable yet interesting. Take it with a pre-blizzard dose of salt.

Sample size be damned, these look cool. This takes the first chart, separates it by year and looks at how certain movements translate to results. In both 2019 and 2020, Karinchak’s curveball whiffs came A) closer to 0 horizontal movement and B) with less drop than curveballs resulting in balls in play.

I did not go crazy trying to adjust for pitch locations or velocities, just simply looked at how movement translated to results. Taking it for what it is, maybe continuing to pursue a Nick Anderson-like 12-6 slurve might be the way to go. 

Karinchak may have had Glasnow’s curveball, but Nick Anderson might just be his best comparison. The high-velocity rising fastball, the heavy breaking dosage (especially in even counts), the absurd strikeout rates. With a 0.55 ERA in 2020, Anderson is what Karinchak would become if he reigns in the walks: The best relief pitcher in the game.

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