Move over, Aroldis Chapman. Mason Miller is the new No. 1 flamethrower in recorded postseason history.
That marked the fastest pitch thrown in the postseason since pitch tracking began in 2008.
Miller’s 104.5 mph heater passed Chapman’s previous mark, which was a 104.2 mph fastball during Game 3 of the 2010 NL Division Series when he was a rookie on the Reds.
But Miller didn’t just top Chapman, he did it on a strikeout. Miller’s 104.5 mph K is the first 104-plus mph postseason strikeout of the pitch-tracking era.
So, was it the best pitch Miller’s ever thrown?
“It’s the best fastball,” Miller said. “Sometimes everything syncs up and the execution is perfect.”
Miller struck out the first eight batters he faced in the 2025 postseason — three in Game 1 and five in Game 2, including the 104.5 mph strikeout of Kelly — before hitting Michael Busch on the lower leg with two outs in the eighth to end the streak. And if you go back to the end of the regular season? Miller struck out 11 batters in a row.
“Doesn’t get much better,” Padres starter Dylan Cease said on the ESPN broadcast after Game 2. “I mean, what was that? Five batters, five strikeouts? That was like a cheat code.”
Miller’s streak of eight straight postseason K’s tied Josh Hader in 2022 for the most consecutive strikeouts in the playoffs at any point, according to the Elias Sports Bureau. And it’s the longest streak to start a player’s postseason career.
“Every pitch feels like it’s coming out good right now,” Miller said. “I feel really good.”
The previous fastest postseason K on record was a 103.7 mph strikeout by Chapman against Jorge Polanco in the 2017 American League Wild Card Game, when he was with the Yankees.
Fastest postseason K’s
Pitch-tracking era (since 2008)
1. Mason Miller: 104.5 mph, Game 2 of 2025 NL Wild Card Series
2. Aroldis Chapman: 103.7 mph, 2017 AL Wild Card Game
3. Mason Miller: 103.3 mph, Game 2 of 2025 NL Wild Card Series
4. (tied) Aroldis Chapman: 103.2 mph, Game 1 of 2016 NLCS
4. (tied) Aroldis Chapman: 103.2 mph, Game 2 of 2016 NLDS
6. Aroldis Chapman: 103.1 mph, Game 4 of 2016 NLDS
7. Aroldis Chapman: 103.0 mph, 2017 AL Wild Card Game
8. Mason Miller: 102.9 mph, Game 1 of 2025 NL Wild Card Series
Miller then added a 103.3 mph strikeout of Dansby Swanson an inning later, giving him two of the top five fastest postseason K’s since pitch tracking began.
“It’s electric stuff,” said Cubs reliever Andrew Kittredge, who pitched as Chicago’s opener in Game 2. “I think the league knows about Mason Miller [and] what he does. That’s about as tough of an at-bat as it gets.”
This also came a day after Miller reached 102.9 mph on a strikeout of Seiya Suzuki in Tuesday’s Game 1 of the Wild Card Series. That was already the fastest postseason strikeout by anyone other than Chapman.
If anyone was going to break Chapman’s postseason velo record, it was going to be Miller. Miller led the Majors in average fastball velocity this season at 101.2 mph, and he’d already broken the 104 mph threshold five times in the regular season before Wednesday’s game — including a 104.1 mph strikeout of the Braves’ Sean Murphy on July 10.
But his 104.5 mph strikeout of Kelly was the fastest pitch of Miller’s MLB career.
Was he saving that extra gas in the tank for the playoffs?
“Not necessarily — but the adrenaline helps,” Miller said. “To get to be here in front of a crowd that’s living and dying with every pitch, it’s pretty exciting.”
