Why Aaron Ashby Increased His Curveball Usage Last Season, and How He's Preparing for a Move Back to Starting

Being sidelined by injury is never fun. Big-league pitchers don't like having to take all the competitive fire and energy that makes them great and channel it into something as controlled, steady, and tedious as rehabbing from injuries. Aaron Ashby, while not known as one of the league's most glove-biting maniacs on the mound, felt the strain of a long time away from the place where feels most at home: a big-league mound. With an active mind, though, improvement is always possible. Last season, while toiling in the minors and awaiting the chance to help the parent club down the stretch, Ashby found a way to improve his arsenal: more curveballs, in a wider variety of counts and locations.

"It’s just something that started working for me," Ashby said Sunday at the Brewers' spring complex in Maryvale. "We used it more when I was in Triple A, after moving to the bullpen. We were having some success with it, and the slider was slow to come back, and after throwing the curveball harder, it actually kind of helped the slider. It was just adjusting to what the arsenal is and what plays."

Indeed, Ashby pushed the velocity on his curve not just back up from the diminished version of everything he had in 2023, but to the highest average speed of his career. When he did, it brought his slider command back—not only precise location, but consistent movement. That's not because there's such a close inherent relationship between the two offerings ("it's a completely different pitch, grip, thought," Ashby said), but because using the curve more often as a sharp, swing-and-miss pitch helped him find the right mechanical cues for the slider.

The slider should be the natural complement to Ashby's fastball; he's always favored a sinker. Because he works out of a higher slot than most sinker-ballers, though, the curve can confound hitters in its own way.

"I think a lot of good curveball guys usually have a four-seam," Ashby said. "So I think [the curve] gets taken more early in counts, because it’s kind of like, ‘whoa, what is that?’ And then as long as I can get it down late in counts, it still plays off that sinker."

The curve not only violates batters' expectations because of that unusually high sinker slot, but is made possible by it. Pitching from somewhere just north of three-quarters, Ashby nonetheless has a fastball shape that befits someone who throws from something much closer to a sidearm angle. Hitters are expecting a four-seamer in the first place, and when they get a sinker, it throws them off.

Then, once they're looking for the sinker, the curve plays up. It's all part of the process of putting hitters permanently on the defensive. Stealing strikes with the curve is nice, but the pitch can be more versatile than that. Last year, once he finished tinkering and discovered the upside of using the curve in multiple ways, it became his primary breaking ball against righties—a very different approach than he's used in the past.

As you can see, though, the most important secondary offering as Ashby tries to return to the rotation hasn't changed. It's the changeup. Ashby acknowledged that keeping that offering sharp when working in relief is difficult, but the pitch is his favorite, and he's eager to get it back to full functionality in 2025.

"Changeup feels good. I want to continue to keep throwing it; I think I’ve only thrown like four up to this point [in the spring]," he said. "But it’s probably my favorite pitch, actually. I think the changeup’s the best pitch in baseball, and if you’re gonna be a starter, I believe you have to have a changeup."

Ashby is still using the same grip he learned in college, watching this video of Max Scherzer demonstrating all his pitch grips. Here's the portion focused on the changeup:

If he can master that offering again—not just getting whiffs with it, but limiting hard contact and deploying it in lots of different situations—it should allow Ashby to thrive in the rotation. On Monday night, watch for him to uncork more changeups as the Brewers visit the Reds in Goodyear—and for his curveball to flummox righties.