San Diego Padres closer Mason Miller is having an inconceivable start to the 2026 season. Through 10 games, he’s allowed two hits and zero runs, with a whopping 25 strikeouts in just 10.1 innings. With his historic start to the season, some have asked if this is the best start to a season by a reliever ever. However, the better question may be whether this is the most dominant run by a reliever ever. With his previous team, the Athletics, he was dominant. With the Padres, he kicked into a second gear. Since joining San Diego after the trade deadline last season, Miller has allowed two runs, which came on a home run by the Arizona Diamondbacks’ Lourdes Gurriel Jr. off a 104 mph fastball. In the Statcast era, and likely MLB history, this was the fastest pitch ever hit for a home run. 

Miller has one of the scariest pitch arsenals to face as a batter. He throws a fastball that tops out at 104 mph, which he couples with a devastating wipeout slider that’s 15 mph slower than his fastball. Also loaded in his repertoire is a 96 mph changeout that he will whip out from time to time. However, Miller was not always the dominant flamethrower that he is today. As a first-year at Division-III Waynesburg University, Miller had a putrid 7.03 earned run average. His dreams of playing baseball past college looked slim. Amazingly, a diabetes diagnosis helped him understand his body better. After this diagnosis, he began to bulk more successfully, allowing him to top out at higher velocities. Thanks to a glucose monitor, he tracks his health at a meticulous level. “Every year since my diagnosis I’ve added weight, muscle and velocity to get into the best shape of my life,” said Miller. 

His adjustment turned his upward trajectory into a launch. Now, he might be the most dominant reliever we’ve ever seen. His 71% strikeout rate is on pace to be the highest ever recorded — and it isn’t close. The current record holder is Aroldis Chapman’s 2014 season with the Cincinnati Reds, where strikeouts constituted 52% of his recorded outs. Miller is relying on the quality of his pitches and his pinpoint precision to dominate batters. As of publishing, Miller has thrown just 31 balls while facing 30 batters. Paired with his 71% strikeout rate, hitters so far have been more likely to strikeout than see two balls in a count. 

Miller has deepened his bag since coming to the Padres, thanks to a higher usage of his slider. During his time with the A’s, the pitch served as a secondary option. It made sense. He has the fastest fastball in the league. Even this season, despite the declined usage, his fastball accounts for 71% of all pitches above 102 mph. Logically, this pitch should be his primary weapon to attack with. However, his reworked slider is even more devastating. Since last year, the late-breaking slider has added 1.6 inches of vertical drop. This new shape has helped maintain an 80% whiff rate on that pitch. He has increased the usage of the slider in general, but specifically against lefties. Against lefties, his slider rate has jumped to 56%, solidifying it as his weapon of choice. Miller has also integrated a changeup, which he uses 7% of the time, forcing hitters to adjust their approach for a complicated array of pitches.  With Miller’s historic start to the season, he has the potential to produce the most dominant reliever season in MLB history if he continues at this pace.