The 105.1 — September 24, 2010

Chapman was 22 years old, in his first month with the Cincinnati Reds after defecting from Cuba. He came in to relieve in the 8th inning of a Reds-Padres game at PETCO Park. The 105.1 was the second-to-last pitch of an 8-pitch at-bat against Tony Gwynn Jr. — the original radar reading was 105.1, then immediately a 105.7 reading came up but was ultimately discarded as a sensor anomaly. The 105.1 stands as the verified record.

Chapman threw 95+ mph on 25 of his 26 pitches in that appearance and got the save, his first as a Red. Reds catcher Ryan Hanigan said in the postgame press conference that he could ‘hear the air change’ on Chapman’s release.

What modern Statcast says about velocity

Statcast began consistently tracking pitches at all 30 MLB ballparks in 2015. Since then, Chapman has thrown the top 50 fastest pitches ever recorded, with no other pitcher within 0.5 mph of his career maximum. Behind Chapman: Jordan Hicks (peak 105.0), Sandy Alcántara (peak 102.8), Jacob deGrom (peak 102.8), Hunter Greene (peak 105.0 — tied with Hicks among non-Chapmans).

League-average fastball velocity has climbed from 91.8 mph in 2008 to 94.1 mph in 2024 — about 0.15 mph per season. Triple-digit (100+ mph) pitches have grown from a once-a-week event to about 1,200 per season league-wide. Pitchers throwing 102+ have grown from 2 (Chapman, Joel Zumaya) in 2010 to 8+ in 2023.

What Chapman had that no one else has matched

Chapman is 6’4″ with an unusually long stride length (about 7’2″ — longer than his height) and a violent left-handed delivery that generates extreme arm speed despite being 220 pounds. He throws from a low-3/4 arm slot and gets unusual extension — releasing the ball about 6 inches closer to home plate than the average MLB pitcher.

He’s pitched for the Reds (2010-15), Yankees (2016-19, 2022), Cubs (2016 World Series-winning relief), Royals (2023), Rangers (2023), Pirates (2024), and Red Sox (2024-25). Two World Series rings (2016 with Cubs, 2017 with Astros — though he was a Yankee that year). His career velocity has dipped slightly from his Reds-era 100+ averages, but he was still throwing 99-100 in his late 30s, which itself is unprecedented.

Background facts cross-referenced with the Wikipedia article on Aroldis Chapman and Pro-Football-Reference / Basketball-Reference public records.