Pitcher · 2026
Justin Slaten
- Age
- 29
- B/T
- R/R
- Height
- 6' 4"
- Weight
- 222 lb
- Number
- #63
- Born
- September 15, 1997 in Longview, TX, USA
- MLB debut
- March 30, 2024
- Drafted
- 2019, round 3
- College
- New Mexico
- dbWAR
- 2.1 3 season(s)
- IP
- 30.1
- ERA
- 4.75
- FIP
- 2.99
- K/9
- 11.3
- FIP−
- 72 100 = avg
Justin Slaten is a relief pitcher for the Boston Red Sox. In 2026 he struck out 38 batters over 30.1 innings across 35 appearances, going 2-4. His ERA of 4.75 was 13.7% higher than the league average of 4.18 — 15th of 17 on his team, and 327th of 467 among MLB pitchers with 20+ innings. Stripping out defence, his 2.99 FIP suggests he pitched better than his ERA shows. He missed bats on 24.9% of swings (12.5% of every pitch he threw), walked 5.3% of the batters he faced and struck out 28.6%. His 0.6 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 | 70 | 67 | 18 | 2 | 2 | 22 | .269 | .290 | .448 | .318 | 31.4% |
| vs RHB | 63 | 57 | 17 | 2 | 5 | 16 | .298 | .355 | .404 | .339 | 25.4% |
Pitch sequencing
What Justin Slaten throws in each count, and what he follows each pitch with. Select any cell for the breakdown.
Select a count to see exactly what Justin Slaten throws in it.
Pitch arsenal
What he throws, how hard, and how often it misses in 2026.
| Cutter | 207 | 93.6 | 2,521 | 51.7% | 19.1% | |
| Four-Seam Fastball | 124 | 96.6 | 2,463 | 48.4% | 19.2% | |
| Sweeper | 82 | 86.1 | 2,635 | 42.7% | 45.0% | |
| Sinker | 57 | 97.2 | 2,376 | 47.4% | 24.1% | |
| Curveball | 17 | 84.6 | 2,710 | 58.8% | 44.4% |
Pitching
Standard and advanced, by season.
| Trend | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | 35 | 0 | 30.1 | 2 | 4 | 0 | 35 | 16 | 38 | 7 | 4.75 | 2.99 | 1.38 | 11.3 | 2.1 | 114 | 72 | 0.6 | |
| 2025 | 36 | 0 | 34.0 | 2 | 4 | 3 | 27 | 16 | 25 | 10 | 4.24 | 3.69 | 1.09 | 6.6 | 2.6 | 102 | 89 | 0.3 | |
| 2024 | 44 | 0 | 55.1 | 6 | 2 | 2 | 47 | 18 | 58 | 9 | 2.93 | 2.61 | 1.01 | 9.4 | 1.5 | 72 | 64 | 1.2 |
Head to head
Put Justin Slaten 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.