Players · S · Pitcher · 2026 regular season
Justin Slaten
- Age
- 29
- B/T
- R/R
- Height
- 6' 4"
- Weight
- 222 lb
- Number
- #63
- Born
- September 15, 1997 in Longview, TX, United States
- MLB debut
- March 30, 2024
- Drafted
- 2019, round 3
- College
- New Mexico
- dbWAR
- 2.3 Regular season, 3 season(s)
- IP
- 31.1
- ERA
- 4.60
- FIP
- 3.04
- K/9
- 11.2
- FIP−
- 73 100 = avg
Justin Slaten is a relief pitcher for the Boston Red Sox. In 2026 he struck out 39 batters over 31.1 innings across 36 appearances, going 2-4. His ERA of 4.60 was 9.9% higher than the league average of 4.18 — 17th of 19 on his team, and 357th of 539 among MLB pitchers with 20+ innings. Stripping out defence, his 3.04 FIP suggests he pitched better than his ERA shows. He missed bats on 25.2% of swings (12.8% of every pitch he threw), walked 5.8% of the batters he faced and struck out 28.5%. 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 regular season.
WAR by season
Pitching Regular season
Standard and advanced, by season. Regular-season games only — postseason games are listed separately below.
Separate from the regular season
Postseason Postseason
Wild Card through World Series. These games are counted on their own: none of them are in the regular-season tables, career totals, league context, leaderboards or dbWAR on this page.
Postseason pitching
| Season | Team | Round | G | GS | IP | W | L | SV | H | ER | HR | BB | SO | ERA | WHIP | K/9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2025 Post | BOS | Wild Card | 2 | 0 | 2.0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 4.50 | 1.00 | 4.5 |
Box-score and rate statistics only. wOBA, wRC+, FIP and dbWAR are measured against a full league season, and a postseason is a few teams playing each other for a month, so they are not computed for October.
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 | 71 | 68 | 18 | 2 | 2 | 23 | .265 | .286 | .441 | .314 | 32.4% |
| vs RHB | 66 | 59 | 17 | 2 | 6 | 16 | .288 | .354 | .390 | .335 | 24.2% |
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, how often it misses, and what hitters do with it.
| Cutter | 211 | 93.6 | 2,519 | 52.1% | 18.6% | 43 | .395 | 1.039 | |
| Four-Seam Fastball | 128 | 96.6 | 2,464 | 50.0% | 20.8% | 36 | .278 | .732 | |
| Sweeper | 87 | 86.1 | 2,630 | 40.2% | 43.9% | 24 | .167 | .564 | |
| Sinker | 65 | 97.3 | 2,379 | 49.2% | 26.5% | 18 | .167 | .377 | |
| Curveball | 17 | 84.6 | 2,710 | 58.8% | 44.4% | 6 | — | — |
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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.