Jacob Misiorowski has maybe the highest ceiling of any pitching prospect in baseball.

In Thursday’s start against the Memphis Redbirds, the flame-throwing right-hander got out of the sixth inning by striking out Luken Baker on a 103-mph fastball. Yeah, you read that right. Miz hit 103 mph on his 78th(!!) pitch of the game. Per Curt Hogg, that had never happened before in the pitch tracking era — neither in the majors nor the minors.

In his previous start, Misiorowski struck out the side in the first two innings. He touched 100 mph on 12 of 33 pitches. That’s 36%, or 9% more than last year’s version of Aroldis Chapman. 2024 Chapman, while somewhat washed, still placed in the 98th percentile of fastball velocity league-wide per Baseball Savant. He’s also a reliever who has never thrown 78 pitches in his 16-year career.

Misiorowski’s fastball last night averaged 98.3 mph. For context, Paul Skenes — hailed as Pitching Jesus upon his arrival in the majors — averages 98.8 on his fastball. It’s clear that Miz throws about as hard as any starting pitcher in MLB today.

He doesn’t just have his fastball, either. From Baseball Savant’s 2024 scouting report:

His wicked slider is now in the low-90s with cutter-ish shape after showing more depth in 2023. He started adding back his curveball to play off his feel for spin after not needing it much in college, and it’s been an impressive whiff generator in its own right in ‘24. He hasn’t used his changeup much to this point, but it’s at least another option.

Misiorowski’s slider percentage is up significantly this year, indicating increased comfort with the pitch. He threw the slider on just 3.1% of his pitches in Triple-A last year. This year? 16.4%, per Fangraphs.

Misiorowski, in terms of pure stuff, is about as good as it gets. The issue was, and always had been, his ability to consistently hit the zone. A lot of the dialogue surrounding Miz before the season centered around whether or not he would ever command his fastball well enough to remain a starting pitcher in the majors.

Keith Law, for example, said in his 2025 prospect overview that he “still believe(s) Misiorowski is 100 percent a reliever.” Law mentioned his high-effort delivery, which he hasn’t “toned down at all since he signed… further point(ing) to a relief role.” Law’s final hypothesis? “I just do not see any way that delivery and command could work in a rotation.”

Then, just like that, something clicked. Misiorowski’s zone rate this year is 53.1%, a career high (last year: 46.4%). His first pitch strike percentage is up from 42% to 51.6%. He’s having the best season of his professional career.

1.46 ERA. 0.89 WHIP. 3.47 BB/9, over two walks lower than last year. He’s figured it out.

What changed?

Misiorowski’s Delivery

The footage below is from 2020, Misiorowski’s senior year in high school. Back then, Misiorowski’s fastball hung out around 90 mph and topped out at 94. He was a few inches shorter (6’4” then, a towering 6’7” now) and hadn’t yet filled out — obviously due to still being in high school.

Even back then, Law’s appraisal of Miz stands true. He had a high-effort delivery. High school Miz stays balanced on his back foot, just like he does today. He explodes toward the plate, just like he does today. Both of those are textbook habits and help a pitcher maintain velocity without sacrificing control.

The two main things that stand out to me about this version of Misiorowski are his stride toward the plate and his follow-through.

What’s interesting to me is that Misiorowski puts his front foot down about as violently as I’ve seen in a high school prospect. Miz doesn’t just land his foot down on the ground — he stomps it. This makes for a choppy, herky-jerky delivery.

As for his follow-through, he’s off balance. The biggest red flag is that Miz doesn’t always land in the same position. Sometimes he lands far off to the left. Sometimes he lands in a more direct line to the plate.

Sometimes Misiorowski remains balanced when he lands, and sometimes he’s stumbling off to the side, out of control. He’s even coming open at times, landing with his front foot to the left of his back foot instead of landing his foot in a straight line (even with both his back foot and the plate).

To me, it looks like high school Misiorowski is trying to manufacture as much velocity as he can with every pitch. This makes sense. He was a highly-scouted pitcher and a second-round pick. He was always projected to continue to grow into his frame and increase his velocity over time. Of course, he wanted to throw as hard as he could as often as he could — that’s the basic instinct that all pitchers have. This rings especially true when you can throw 94 mph at age 17 and have scouts at all of your games.

It took Miz a while to work through this in the pros as well. Baseball Savant’s 2022 scouting report on Misiorowski:

Cutting a thin figure and pitching exclusively out of the stretch, Misiorowski can look like all elbows and knees in his up-tempo delivery as he attempts to fire pitches past hitters. It isn’t always a repeatable delivery, and while the strikeouts can pile up, so can the lengthy plate appearances and eventual walks. Most believe he’s headed for a high-leverage bullpen role as a right-handed Josh Hader who could help the Crew this summer.

Now, watch the film from Miz’s High-A debut in early 2023. By this point, Miz has smoothed out his delivery a lot. His front foot is less choppy — instead of coming up, then out and violently down at the same time, he’s developed a less pronounced version of a Kershaw-esque slide step (up, down, then out).

Pitching motions are very individual. There are some things that don’t work for anybody (such as coming open), but most of pitching is about finding out what mechanics work for you and your body, finding mechanics that help you stay stable on your back foot and drive forward in a controlled yet powerful way. Shoutout to Ukiah, California legend Robby Rowland (and his brother Rich, who coached me in high school) for this great breakdown of Kershaw’s mechanics and why his delivery works for him.

As you can see, Kershaw’s delivery works in part because it helps keep his weight on his back leg as long as possible. High school Misiorowski stayed balanced on his back leg, but sometimes lost balance when he shifted to the front leg (hence the choppy delivery). By shifting his weight to the front leg later in the delivery (e.g., Kershaw), he’s able to play to his strengths and stay balanced for longer. Implementing more of a slide step ended up helping stabilize Misiorowski’s delivery. His motion is, in general, a lot smoother and more balanced than it was in high school. Again, though, there are still inconsistencies.

All you need to watch is the first two pitches of the above highlights — both strikeout pitches. On his first pitch, Misiorowski’s form is textbook. He comes up, stays balanced, stays on his back foot longer than he did in high school, and then explodes toward the plate in a controlled yet violent manner. Miz also finishes balanced.

Compare this to the next strikeout pitch at 0:25. It’s a great pitch, but not a great throw. Misiorowski comes open a bit and finishes off balance. His front foot lands to the left of his back foot and to the plate. As he’s falling to the left, he opens his arm and releases just a bit earlier. That keeps the ball on line and gets him the strikeout. Essentially, this version of Misiorowski is adjusting for the inconsistencies in his delivery in real time. Even when he’s pitching well and getting strikeouts, his delivery is inconsistent.

That works sometimes for a freak athlete like him, but it doesn’t work all the time. A successful major league pitcher will have the same mechanics every time, which Misiorowski, at this stage in his career, wasn’t able to do.

This next video is from Misiorowski’s 2024 stint with Triple-A Nashville. The evolution is, again, clear. Other than at 0:04 (when he again comes open), most of his pitches are missing up or down in the zone. 2024 Miz isn’t usually missing pitches because of his mechanics, he’s missing pitches because he’s throwing as hard as he can (more on this later). Misiorowski doesn’t always finish balanced (e.g., 0:18), but even when he misses, he’s more often throwing in a straight line to the plate. He’s not coming open as much, not falling off to the side as much, and the slide step is even more prominent than it was in 2023.

The final piece to the puzzle is, simply, his last few outings. As we’ve established, Misiorowski’s control is better than it’s ever been. This chart from a commenter on the Brewer Fanatic forums does a great job of breaking it down. There are a few stats worth analyzing — I could talk about strike percentage, zone percentage, etc., all day if I had an unlimited word count.

All you need to do to understand that his control has improved significantly is look at the pitch location chart at the top of the post. Go look at where exactly every pitch landed — even when Misiorowski misses, a higher percentage of his misses are close to the zone.

Now, watch the film from Misiorowski’s start a couple of weeks ago.

His mechanics are consistent. Every. Time. When he’s off balance (the last strikeout shown), it’s because he slipped, not because he opened up his delivery and ended up falling off the mound. Even when he’s off balance, the delivery is consistent up until the ball’s already out of his hand.

The slide step is also smoother. Misiorowski gets crazy extension on his delivery (a reported 7 ¹⁄₄ feet on average), which makes it easier to land inconsistently on his front foot. He doesn’t do that anymore — on every strikeout, his front foot lands in basically the same place.

All of this also helps Misiorowski develop as a pitcher. It’s not just locating the fastball. He’s locating all of his pitches better. That’s why he’s throwing more sliders than ever this season — he can command them now. If his slider becomes a go-to pitch, that’s going to make him even more unhittable.

Don’t take it from me, though. Brewers pitching coach Chris Hook had this to say near the end of last season:

“Stuff is one thing. You get that naturally. Routine is going to be the key to (Misiorowski’s) success. He has two tremendous breaking balls. Fastball command is key. He moved very fast. Part of his routine is getting to understand how his body moves and getting on time with that. We don’t want to slow that down, we want to control. When he starts getting that down, the command will come.”

That is exactly what Misiorowski has done. He has controlled his delivery. It’s still violent and explosive, but now it’s both smoother and way more consistent. See for yourself — go back and watch high school Miz again, then watch his highlights from last night. The results speak for themselves. He’s figured it out.

Misiorowski’s Mental Game

The other aspect of Misiorowski’s development worth mentioning is the mental side to being a flamethrower. As I mentioned while analyzing Misiorowski’s high school highlights, it often seemed like he was trying to throw as hard as he could. As Coach Rich used to say, there’s a difference between being a pitcher and a thrower.

Baseball America wrote an article on Thursday about Misiorowski’s record-setting 103-mph fastball. The way they framed it speaks to the other notable development in Misiorowski’s delivery, which is less apparent in highlights and more apparent when you tune into a Nashville Sounds game. From BA:

“In the maturation of a pitcher, it was another key step. The righthander didn’t just try to rear back and blow away the Memphis lineup. He paced himself, getting outs with high-90s fastballs and hard low-90s sliders for most of the game.”

This, to me, is just as big. Pitching is mental as much as it is physical. Misiorowski, who has a wicked three-pitch arsenal (curveball, four-seam, slider) and a still-developing changeup, doesn’t need to touch 103 mph every outing to be lights out. He very well might, seeing as he’s clearly found a way to ensure his delivery is more consistent without sacrificing high-end velocity. However, sometimes you just need to bear down and get an out. Misiorowski can do that now. He’s now a pitcher, not a thrower.

I kind of like the idea of bringing Misiorowski out of the bullpen to start, a la rookie Chris Sale. Sale’s obviously a lefty, but other than that, he was a similar prospect — tall, hard-throwing, and had some control issues in his youth. Sale came out of the bullpen in his first two seasons before transitioning to the rotation.

Milwaukee does have a lot of starting pitching options (although half of them are on the IL), and Misiorowski — like Sale — might benefit from low-stress relief appearances to ensure his delivery stays consistent as he adjusts to facing the best hitters on the planet. He would also probably be really, really good in that role.

However, Misiorowski has proven this season that he is a starting pitcher. He will undoubtedly be given a chance to start games in the majors. Hopefully, that opportunity comes soon.

Next up: Josh Adamczewski/Cooper Pratt (whichever one I can find more film on).

Who else would you like to see covered in a future “Minor League Film Room?” Comment your ideas below to be considered for future coverage!