Jacob Misiorowski's Sensational Outing Highlights Why His Curveball is Key to His Success

Early in 2025, Jacob Misiorowski has faced the same issues with his overall stat line as in previous seasons—namely, high walk rates and too many hit batsmen. The thing is, it's for an entirely different reason. In a departure from past seasons, Misiorowski has rarely been outright wild. Instead, he's nibbling around the edges of the tighter zone forged by the challenge system in place throughout Triple A. No, his issue this year has been how to put away the more experienced hitters in the international league.

Specifically, his command of breaking stuff has allowed him to fill up the zone better. The cutter/slider has been his main source, pounding the zone over 61% of the time with it in his first four starts, but despite having slider-like movement at 94 mph, that's probably his least effective pitch for putting hitters away. He gets less swing-and-miss with the slider, and has given up some hard contact when leaking it over the heart of the plate. It also doesn't tunnel as effectively with his four-seamer, and throwing it more has dampened the swing-and-miss on his primary offering.

Enter the curveball. That's another pitch he's had no problem locating in the zone this season. He significantly upped its usage last night, to roaring success:

The first chart is for Misiorowski's first four games of the season; the second is from yesterday's game (there is also a token changeup classified as a fastball for those with eagle eyes). Misiorowski was feeling his fastball, reaching an average velocity of 98 mph with great extension and movement, but the increased usage of his curveball from 11% to 27.6% is a massive jump, all coming at the expense of the slider. It's had better whiff rates all year, and more importantly, it tunnels effectively with his four-seamer at the top of the zone. 

That strong negative induced vertical break number means that hitters have to be aware of not just the rising fastball above the zone, but of the danger of the ball dropping off a cliff and landing in the zone—a prevalent occurrence in his recorded strikeouts from last night.

Misiorowski has been getting ahead in the count more often this season, with significantly less wildness. If he can maintain this type of pitch mix (with occasional sliders and changeups, to keep hitters off-balance), he may have found an arsenal that he can really command at the big-league level.

He did find the zone more often with his four-seamer, as well—up to 49%, from a season average of 43.9%—and that's important, too. Bringing that type of control to a big-league strike zone would bring him close to league average in how often he lands it in the strike zone, but the combination of the curveball and fastball from a pure stuff perspective (as well as how they play off one another) is going to be key for Misiorowski moving forward.

Obviously, we will need to see more of this than just the 76-pitch sample that was Tuesday night. Still, Misiorowski has struggled to show this kind of efficiency even in his best outings in recent years. How he backs this up in his second start of the week on Sunday will be fascinating.

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