Every pitch exceeded 103 mph—nowhere to hide
On a June evening in Milwaukee, a young starting pitcher named Jacob Misiorowski did something no one in the long history of Major League Baseball had done before — he threw a fastball at 104.5 miles per hour from the starting rotation, a place where endurance has always been thought to temper raw power. The achievement invites a quiet but serious question: are we witnessing the outer edge of human physical possibility, or merely the opening of a new frontier in how pitchers are made?
- With a 2-2 count against one of baseball's most dangerous hitters, Misiorowski unleashed a 104.5 mph fastball that rewrote the record books in a single instant.
- Every pitch in the at-bat exceeded 103 mph — Schwarber could anticipate the fastball and still couldn't catch up to it, exposing the raw gap between knowing and doing.
- The radar gun briefly flashed 105 before settling at 104.5, a number that sparked immediate debate and will fuel conversations about pitcher performance standards for years.
- Aroldis Chapman's all-time MLB record of 105.8 mph still stands, but the wall between reliever dominance and starter capability has never looked thinner.
- Misiorowski's night raises an urgent question for the sport: is extreme velocity becoming sustainable across full starts, or was this a singular collision of talent and circumstance?
On a Friday night in June at American Family Field, Jacob Misiorowski stood on the mound in the first inning and faced Kyle Schwarber with the count at 2-2. What followed was a moment baseball had never seen — a 104.5 mph fastball from a starting pitcher, the fastest ever recorded at that position in Major League Baseball history. Schwarber could only nick it, Catcher William Contreras secured the out, and while Schwarber argued the call, the scoreboard had already written a different headline.
What amplified the record was its context. Misiorowski didn't reach 104.5 mph in isolation — every pitch he threw to Schwarber that at-bat exceeded 103 mph, including a 104 mph called strike earlier in the sequence. For a hitter facing a starter, the expectation is that velocity will fade. Against Misiorowski, it never did.
The broader record still belongs to Aroldis Chapman, the Red Sox reliever who threw 105.8 mph in 2010 and matched near that intensity again in 2016. But Chapman was a reliever, built for short, maximum-effort bursts. Misiorowski is a starter — expected to manage his arm across multiple innings every fifth day. That he could sustain such extreme velocity through an entire at-bat points to something shifting in how modern pitchers are developed and conditioned.
Whether Misiorowski's night signals a new era for starting pitcher velocity or stands as a rare outlier remains an open question. But the record is his now, and the game's quiet, incremental evolution had one of its more visible moments on an otherwise ordinary June evening in Milwaukee.
Jacob Misiorowski was standing on the mound at American Family Field on a Friday night in June, facing Kyle Schwarber in the top of the first inning. The count ran to 2-2. What happened next would become the fastest pitch ever thrown by a starting pitcher in Major League Baseball history.
The ball left Misiorowski's right arm at 104.5 miles per hour. It caught the lower outside corner of the strike zone, and Schwarber, trying to check his swing, managed only to nick it. Catcher William Contreras held onto the result for the out. While Schwarber began arguing the call with the umpire, the scoreboard told a different story—one that would dominate the conversation for days. The radar gun initially read 105 mph before official measurement settled on 104.5, a record that belonged to no one before this moment.
What made the achievement even more remarkable was the consistency of Misiorowski's heat. Every single pitch he threw to Schwarber that at-bat exceeded 103 miles per hour. The third pitch of the sequence, a called strike, also touched 104 mph. For a hitter facing a starting pitcher, there was nowhere to hide. Schwarber was essentially locked in against a fastball he could see coming but could not catch up to.
The record is significant but not unprecedented in baseball's broader context. Aroldis Chapman, the Red Sox reliever, still holds the all-time mark. Chapman threw a 105.8 mph fastball in 2010 during his rookie season with the Cincinnati Reds, when he was still establishing himself as one of the game's most dominant arms. He matched that intensity again in 2016 with the Chicago Cubs, throwing a 105.7 mph fastball. Chapman's records have stood for over a decade and a half.
But there is a meaningful distinction between what Chapman did and what Misiorowski accomplished. Chapman was a relief pitcher, brought into games for short, high-leverage appearances where maximum effort is the expectation. Misiorowski was a starter, tasked with pitching multiple innings and managing his workload across a full game. The velocity he generated—not just once, but repeatedly—suggests something is shifting in how modern pitchers are built and trained. The fact that he could maintain such extreme heat through an entire at-bat, throwing nothing below 103 mph, indicates a level of physical capability that previous generations of starting pitchers did not regularly demonstrate.
The Brewers-Phillies matchup on that June evening became a footnote in baseball history, one of those moments where the sport's incremental evolution becomes suddenly visible. Misiorowski's arm, that cannon he carries, rewrote what is possible for a pitcher who is expected to take the ball every fifth day and compete for six or seven innings. Whether this marks the beginning of a new era in starting pitcher velocity, or whether Misiorowski's night was an outlier of exceptional talent and circumstance, remains to be seen. But the record is now his, and the radar gun does not lie.
Notable Quotes
The scorebug initially read 105 mph before official measurement confirmed 104.5 mph— Official MLB radar gun reading
The Hearth Conversation Another angle on the story
What does it mean that a starting pitcher threw 104.5 mph? Why does that distinction matter?
Starters are supposed to be durable, not explosive. They pitch deep into games. Relief pitchers—the guys Chapman was—they come in for one or two innings and empty the tank. Misiorowski did this as a starter, which changes the conversation about what human arms can sustain.
Did Schwarber have any chance against pitches that fast?
Not really. He got a piece of one, barely. When every pitch in an at-bat is over 103 mph, you're not hitting it—you're hoping to make contact. It's a different kind of baseball.
Chapman's record is still higher. Does Misiorowski's achievement feel diminished by that?
No. Chapman threw harder, but he was a specialist brought in for moments. Misiorowski did this as his job, his role in the game. They're different accomplishments.
What happens next? Does this change how teams think about starting pitchers?
That's the real question. If other young starters can generate this kind of velocity, it reshapes everything—workload management, pitch design, how hitters prepare. One night doesn't make a trend, but it plants a seed.
Was this a fluke, or is Misiorowski just built differently?
We don't know yet. One at-bat, one game. But the fact that all five pitches exceeded 103 mph suggests it wasn't a one-time spike. There's something real there.