Until Wednesday, Jacob Misiorowski Hadn't Even Shown Big-League Hitters His Best Fastball

It was evident throughout his time in the minor leagues, and a wider audience learned it in his big-league debut: Jacob Misiorowski’s fastball is an outlier pitch. Its velocity, movement, and release point (in three dimensions, with an unusually low release height and enormous extension toward the plate) make it unlike any heater most hitters are accustomed to facing.

“He’s standing right next to you, you know?” said Eric Haase, who caught Misiorowski in his third start on Wednesday against the Pittsburgh Pirates. “The extension is a real thing.”

“I feel like his [fastball] is a lot harder than mine, just because he's like eight feet out towards home plate,” said fellow flamethrower Trevor Megill.

The early results were already exceptional. Misiorowski’s four-seamer did not allow a hit through his first two starts and induced plenty of uncomfortable swings. However, the helpless swings and misses it's capable of generating were more fleeting. After it notched a 33.1% whiff rate against Triple-A hitters this year, MLB opponents whiffed on 19.2% of swings through those first two outings.

Misiorowski outdueled Pirates ace Paul Skenes by unleashing that fastball’s full potential for the first time in a big-league start. After he and William Contreras used a more balanced mix his first two times out, the right-hander and Eric Haase let the heater eat. It carved through Pittsburgh hitters, inducing 10 swings and misses.

“Just kind of seeing how they’re handling the heaters,” Haase said. “I feel like if he does get hurt, it’s going to be guys just so much on the heater that they kind of run into a breaking ball out in front. So just trying to pick our spots when it looks good and stay on the heater.”

Location was the greatest difference. Misiorowski commanded his fastball more consistently at the top of the zone, where its velocity and gravity-fighting backspin from his low slot work best to yield late swings.

“His high fastball is something to be watching,” Megill said. “That thing’s really nice.”

It also helped that Misiorowski had an extra notch of that backspin-induced carry. In his first two starts, his four-seamer averaged 16 inches of induced vertical break. On Wednesday, it averaged 17 inches. That's no surprise. Movement and location are linked, and when a pitcher elevates the way Misiorowski did Wednesday, they usually get a bit of extra ride.

“I think I was staying pretty true on my delivery and really getting a lot of vert on it,” he said, “so I think that helped a lot.”

Misiorowski has teased how high his ceiling can be every time he has taken a big-league mound. His latest effort was enough to outpitch Skenes. It was the first glimpse at how untouchable he can look when that fastball is fully clicking.