I have always found the starter-into-closer pipeline to be demoralizing. Per baseball truisms, even the best reliever would be a starter if they were only, by certain definitions, better. Moving a starter to the pipeline is so often the last-ditch move of teams that do not know how to develop their pitchers. I hope Roki Sasaki finds his groove; I hope that closer-into-starter conversion or reconversion projects go well.
That said: Mason Miller, who was traded from the Athletics to the San Diego Padres last year for a whopping four prospects, was practically engineered in a lab to be the exception. The closer is a position in baseball where the best players are, value and contracts and whatever bullshit aside, composed of pure, distilled coolness. It is a different skillset from that of the starter. A closer—who does not have to worry about pitch count, or keeping the arm going through five-plus innings, or the third time through the batting order—is more concerned with quality, delivering more concentrated nastiness on the pitch-to-pitch level than starters can. For Miller, this is best exemplified by his average four-seamer speed going up a full three miles per hour after he moved to the bullpen. Also, now he gets a cool walk-out ritual (depending on one's definition of cool).
It is fine, even appealing, that Miller's arsenal is composed of only an absurd fastball, an absurd slider, and an occasional changeup to lefties, thrown so infrequently that the pitch's heat map so far this season resembles six little bullseye targets. A closer with Miller's stuff does not need more pitches than that. His fastball sits at 101.4 mph and touches 103, which does legitimately make his 95.8-mph change-up a change-up. So far this season, 24 pitches have been thrown above 102 mph. One was thrown by Baltimore Orioles reliever Ryan Helsley; six have been thrown by Los Angeles Dodgers reliever Edgardo Henriquez (rocking, despite the stuff, a 5.40 ERA). Miller threw the other 17.
To complement the fastball, Miller's slider sits at 87.8 mph with hugely above-average horizontal and vertical break. While the fastball is the one with the obvious, eye-popping velocity, Miller's slider actually generates the most run value for him, and the pairing at the root of his success. This 10-pitch, three-up, three-down sequence against the Colorado Rockies from a week ago is illustrative:
Mason Miller.10 pitches. 3 strikeouts.103 with THAT slider isn’t fair. 😳
— Rob Friedman (@pitchingninja.com) 2026-04-10T12:27:29.074Z
Miller was always nasty, but he has somehow reached new heights to start this season. In nine appearances, Miller has walked one batter, allowed a hit to another, and has otherwise posted a completely clean sheet. He got those pockmarks out of the way early, and has an ongoing streak of seven perfect innings. He has a 0.00 ERA (I love significant figures) and an absurd 0.21 WHIP.
Every pitch Miller throws looks untouchable, and the statistics concur. What do you think is a good strikeout rate for a relief pitcher? 35 percent? Maybe a guy on an extremely hot streak will strike out batters 50 percent of the time? Well, try a 76.7 percent strikeout rate so far this season: Miller has struck out 23 of the 30 batters he's faced. Put another way, six out of Mason's nine appearances have ended with him striking out the side.
Sample size obviously plays a part here, as Miller is still waiting for a really true heavy-duty hitter to embarrass this year. But seeing as the next-closest reliever in strikeout rate, at 44.4 percent, is Pirates reliever Mason Montgomery—clearly the first name is a hack, though Montgomery is of the Henriquez school of 5.40 ERA—Miller is an early-season outlier among early-season outliers. He feels due for an immaculate inning; that is not a normal feeling to have.
Thursday night, Miller put on another show against the Seattle Mariners, who in turn put on their own show of last-ditch ABS challenges: the only thing a team can really do, nowadays, in the face of Miller's stuff. It was his sixth all-strikeout appearance of the year, but he still managed to do it in style.
The only thing better than three swinging third strikes would be three—
—called—
—third strikes.
It's just totally unfair, man.
