Brewers Jacob Misiorowski’s Fatigue Cause For Concern? Fastball Takes a Dip

Analyzing Jacob Misiorowski's dip in fastball velocity.

Aug 21, 2026; Milwaukee, Wisconsin, USA; Milwaukee Brewers starting pitcher Jacob Misiorowski (32) throws a pitch in the first inning against the Atlanta Braves at American Family Field. Mandatory Credit: Benny Sieu-Imagn Images | IMAGN IMAGES via Reuters Connect

The Milwaukee Brewers' 24-year-old phenom Jacob Misiorowski is the first starting pitcher that Major League Baseball has ever seen who is consistently pumping 103-mile-per-hour fastballs deep into games. 

He himself did not invent the trend of high-velocity starting pitchers; however, he has inarguably become the face of it. He is the runaway favorite to bring home the NL Cy Young with his 1.68 ERA and league-leading strikeouts. 

Friday night, he added six Ks as he went toe-to-toe with future Hall of Famer Chris Sale, besting the veteran and earning his 13th win of the season. 

Now, I am not here to rain on the parade of the league’s most exciting pitcher. However…

Something was off on Friday night. Misiorowski once again flexed his league-best stuff, but it wasn’t his trademarked four-seam fastball that got him into the shutout in the seventh inning. 

As  MLB.com’s Adam McCalvy pointed out, Misiorowski turned to his slider or cutter on a season-high 39.6% of his 96 pitches thrown. This is a 60% increase from his usual total of 24% combined usage for the two pitches. 

It is worth reminding baseball fans that this is the first full season The Miz has pitched at the Major League level. He has already nearly doubled last season's pitch total of 1,164 in 15 appearances. 

Of his 2,083 pitches thrown this season, 1,331 of them have been four-seam fastballs. The average velocity of those 1,300 fastballs is a blistering, jaw-dropping 100.7 MPH. 

The hypothesis is simple: we do not know what 1,500 triple-digit fastballs will do to a starting pitcher's arm over the course of a full season. 

Brewers Clubhouse Reacts To Misiorowski’s Fastball Dip

Misiorowski himself told reporters today that something felt off (which sparked this whole research project in the first place). 

“The offspeed felt great. I felt that was the only thing I had ‘on’ today,” Misiorowski said. “The body felt a little off. Nothing weird. It was one of those days where it was just a down day. I had to grind through it and make it work.”

Manager Pat Murphy answered a targeted question by conceding that, yes, fatigue could have been a factor in Friday’s pitch selection.

“There could be some fatigue involved here, but we’re trying to get him to understand that you don’t have to feel great to perform great,” Murphy said. “I think he’s getting that.” 

Relief pitcher Trevor Megill, however, did not hesitate to tell us what we really need to hear.

“It’s 100-101 [mph]. It’s a tick down. You guys are spoiled,” Megill said. “He’s growing in front of us. It’s a guy getting more mature with his stuff and his arsenal. We’ve been fortunate to see it on our side of the field.” 

Maybe we are all reading too much into it, but Misiorowski will continue to be under a microscope as long as he continues to be the best pitcher in baseball. It comes with the territory. 

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