MLB
Misiorowski’s 103.5 MPH Pitch Sets World Series Tracking-Era Record
His first pitch surpassed Chapman’s 103.2 mph mark. MLB’s comparison begins in 2008 and uses release-speed data across different generations of tracking equipment.
Jacob Misiorowski’s 103.5 mph opening fastball against Yandy Díaz in World Series Game 1 set a record within MLB’s pitch-tracking era. The league’s report places the beginning of that comparable World Series record in 2008.
The Brewers right-hander surpassed Aroldis Chapman’s 103.2 mph pitch for the Cubs in Game 2 of the 2016 World Series. The difference between the published readings is 0.3 mph. The category is World Series pitches measured within that tracking record.
| Pitcher | World Series Appearance | Reported Speed (mph) |
|---|---|---|
| Aroldis Chapman | Cubs, Game 2, 2016 | 103.2 |
| Jacob Misiorowski | Brewers, Game 1, October 23, 2026 | 103.5 |
Which Speed Is Being Compared?
Baseball Savant’s CSV field definitions identify pitch velocity as release_speed, expressed in miles per hour. For 2008–16, the values come from PitchFX and are adjusted to approximately the point where the pitcher releases the ball. From 2017 onward, the values come from Statcast and are reported at release. The documentation explicitly puts those historical readings on the same scale.
That definition matters when comparing a 2016 pitch with one from 2026. The published number describes release speed, rather than a measurement taken at an unspecified point on the way to the plate. A historical comparison needs both the number and the location the measurement represents; a different label should not silently be treated as equivalent.
Why the Record Begins Before Statcast’s Full Rollout
MLB’s Statcast glossary says pitch-tracking hardware reached every Major League stadium in 2008. Statcast followed after a partial 2014 trial and was installed in all 30 ballparks in 2015. Its 2015–19 system combined cameras and radar. Hawk-Eye’s high-speed camera system arrived in 2020.
The historical record therefore spans more than one generation of equipment. The 2008 boundary and the later Statcast rollout describe different stages in that development. Savant’s release-speed definition explains how the older velocity values are presented alongside newer ones; the shared record does not require the original hardware to have remained unchanged.
Why 103.5 Can Set This Record After a 104.8 Pitch
Misiorowski’s earlier 104.8 mph first pitch against San Diego came in NLDS Game 1 on October 3. That higher reading belongs to an earlier postseason round. It does not conflict with a new World Series record at 103.5 mph, because the World Series is a narrower category than the entire postseason.
Earlier World Series pitches fall outside this comparison’s complete tracking record. Missing comparable measurements cannot establish that those pitches were slower. The supported finding is a new high within a defined record beginning in 2008.
