Pitcher · 2026
Isaac Mattson
- Age
- 31
- B/T
- R/R
- Height
- 6' 2"
- Weight
- 214 lb
- Number
- #72
- Born
- July 14, 1995 in Erie, PA, USA
- MLB debut
- May 7, 2021
- Drafted
- 2017, round 19
- College
- Pittsburgh
- dbWAR
- .9 3 season(s)
- IP
- 34.2
- ERA
- 4.93
- FIP
- 3.78
- K/9
- 8.6
- FIP−
- 91 100 = avg
Isaac Mattson is a relief pitcher for the Pittsburgh Pirates. In 2026 he struck out 33 batters over 34.2 innings across 36 appearances, going 0-0. His ERA of 4.93 was 18.1% higher than the league average of 4.18 — 9th of 14 on his team, and 344th of 467 among MLB pitchers with 20+ innings. Stripping out defence, his 3.78 FIP suggests he pitched better than his ERA shows. He missed bats on 22.1% of swings (11.0% of every pitch he threw), walked 10.3% of the batters he faced and struck out 21.2%. His 0.3 dbWAR is built from that FIP rather than runs allowed, so it credits him for what he controls and not for the defence behind him.
League context
Percentile among qualified pitchers, 2026.
Platoon splits
How left- and right-handed hitters fare against him.
| Split | PA | AB | H | HR | BB | SO | AVG | OBP | SLG | wOBA | K% |
|---|---|---|---|---|---|---|---|---|---|---|---|
| vs LHB | 82 | 70 | 21 | 2 | 11 | 17 | .300 | .390 | .500 | .389 | 20.7% |
| vs RHB | 74 | 68 | 17 | 1 | 5 | 16 | .250 | .311 | .353 | .299 | 21.6% |
Pitch sequencing
What Isaac Mattson throws in each count, and what he follows each pitch with. Select any cell for the breakdown.
Select a count to see exactly what Isaac Mattson throws in it.
Pitch arsenal
What he throws, how hard, and how often it misses in 2026.
| Four-Seam Fastball | 458 | 94.1 | 2,350 | 51.3% | 20.2% | |
| Slider | 77 | 84.2 | 2,212 | 49.4% | 27.9% | |
| Changeup | 63 | 86.0 | 1,267 | 33.3% | 21.1% | |
| Sweeper | 50 | 82.9 | 2,324 | 40.0% | 30.8% |
Pitching
Standard and advanced, by season.
| Trend | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | 36 | 0 | 34.2 | 0 | 0 | 0 | 38 | 19 | 33 | 16 | 4.93 | 3.78 | 1.56 | 8.6 | 4.2 | 118 | 91 | 0.3 | |
| 2025 | 44 | 0 | 47.2 | 3 | 3 | 0 | 35 | 13 | 45 | 19 | 2.45 | 3.66 | 1.13 | 8.5 | 3.6 | 59 | 88 | 0.5 | |
| 2024 | 3 | 0 | 5.1 | 0 | 0 | 0 | 1 | 3 | 6 | 5 | 5.06 | 4.29 | 1.13 | 10.1 | 8.4 | 124 | 105 | 0.0 |
Head to head
Put Isaac Mattson beside up to three others.
Similar players
Nearest 2026 seasons by command, run prevention and role, on rate statistics rather than totals.
wOBA uses linear weights measured from this season's own play-by-play rather than published constants, and wRC+ is park-adjusted against that same league. dbWAR is our own open implementation — not fWAR or bWAR — and the full derivation, including its simplifications, is on the methodology page.