Mason Miller Is Making Closers Look Ordinary
Mason Miller is 17 appearances into the 2026 season, has allowed 2 runs, and has been the most dominant reliever in baseball. The numbers aren't a fluke.
By The Numbers
The Strikeout Machine
34 strikeouts in 61 batters faced. That's a 55.7% strikeout rate — more than double the league median of 21.8%. He's also walking just 5.2% of batters faced, compared to the league median of 9.0%.
The chart below puts those numbers next to the rest of baseball's qualified relievers.
The Slider That Doesn't Exist
Most of this comes down to one pitch.
Miller's slider, which he throws 52% of the time, sits at 87.7 mph with sharp horizontal break. Batters are swinging and missing at a 72.5% whiff rate — for context, 40% is considered elite. The xwOBA against it is .034. He's thrown it 119 times this season. Zero extra-base hits.
The Fastball That Sets Everything Up
What makes the slider work is the fastball behind it. Miller's four-seamer averages 101.2 mph and has touched 103.8. It's not just a setup pitch either — batters are whiffing on it at a 42% rate when they swing.
The sequencing is pretty simple: fastball to set it up, slider to finish. After a slider, he throws another slider 59% of the time. After a four-seam, he repeats 51% of the time. When he gets to 0–2, slider usage climbs to 66%. Hitters know it's coming. Doesn't matter much.
| Pitch | Usage | Avg Velo | Max Velo | Whiff% | xwOBA |
|---|---|---|---|---|---|
| Slider | 87.7 mph | 90.0 mph | 72.5% | .034 | |
| 4-Seam Fastball | 101.2 mph | 103.8 mph | 42.0% | .264 | |
| Cutter | 88.3 mph | 89.2 mph | 50.0% | — | |
| Changeup | 95.8 mph | 97.0 mph | — | — |
Contact Quality When He Does Get Hit
When hitters do make contact, they're not doing much with it. Over 23 batted balls this season, Miller's hard-hit rate is 17.4% against a league median of 24.6%. Max exit velocity allowed: 98.6 mph.
Win Probability Added
WPA measures how much a pitcher moves the needle on winning or losing in each appearance. Miller has been positive in all but one outing this season. And that was because he came in with an 8-2 lead so the team's WP was already rounded to 100%. The bars below are individual games; the red line is the running total.
The Big Picture
Miller throws a 101 mph fastball and a slider that batters are whiffing on 72% of the time. He's 17 appearances in and has given up 2 runs all season. At some point the conversation shifts from "is he having a great year" to "how good can this actually get."
We'll keep updating as the season goes on.