Justin Slaten

P Boston Red Sox
Age 29 RHP 6'4" / 222 lbs MLB peak 0.4 · 2027 ILInjured 60-Day (D60)
Overview
MLBRPD6040-MAN
YearAgeLvl / TeamGGSIPERAFIPK%BB%WARMLE rates
202426MIX2 levels450563.072.4526.0%4.4%1.4K 25.9% · BB 4.0% · FIP 2.43
202527MIX2 levels390373.893.2620.1%6.0%0.6K 18.2% · BB 5.8% · FIP 3.53
202628MIX3 levels382334.322.8929.5%6.2%0.7K 28.5% · BB 5.8% · FIP 3.08
2027PROJ29MLBBOS330353.503.4026.5%5.1%0.5
2028PROJ95% MLB30MLBBOS500523.563.6025.8%5.4%0.6
2029PROJ95% MLB31MLBBOS460483.733.8425.0%5.7%0.4
Last 3 seasons WAR 2.6  ·  Next 3 projected WAR 1.5Projected rows: MLB playing time only, park and league context applied.
Contract
No contract data on file.
Skills · percentileStatcast 2026
xwOBA vs90
K%84
FB Velo79
Whiff%50
CompsDavid Carpenter (age 29) · Jumbo Diaz (age 30) · Kiko Calero (age 29)
2027 FULL-SEASON PROJECTIONrates below = full-season projection
showingPROJ
wRC+ AGAINSTvL 9890vR 82
ERA3.50
FIP3.40
K%26.5%
BB%5.1%
K-BB%21.4%
Proj IP35
Value2027 · WAR
Runs saved vs league avg · 35 IP
K: +1.8 runs (Runs saved by strikeouts vs lg-avg K%)+2KBB: +2.2 runs (Runs saved by walk suppression vs lg-avg BB%)+2BBCONTACT: -0.9 runs (Runs saved on contact quality (HR suppression) vs lg)-1CONTACTSTAM: +1.4 runs (Replacement credit for innings volume)+1STAMTotal WAR: +0.47 (35 IP)+0.5WAR
0.50.60.4272829
Grades · Statcast · Arsenal · Contract
Scouting Grades
STUF5555
CTRL6565
CMD5555
K†6060
Statcast Percentiles
FB Velo
p7996.6
Whiff%
p5025.2%
K%
p8428.5%
xwOBA vs
p900.266
FB+0.8 (38%)
CT (42%)
SI (13%)
CU (3%)
SL (17%)

Contract

No contract data on file. Pre-MLB players and minor-league free agents do not yet have salary projections — entries are added at first 40-man roster placement.

Career Stats + Projections

Real MLB stats plus park-adjusted projections — this season (so far / rest / full), then future seasons and career totals.
basis chips: RAW = as recorded · CTX = with park/league context · A+C = actual + context combined · MLE = level/park-neutral
Methodology▸ how WAR & MLE are computed

Stats are park-neutral MLB equivalents. The "TEAM" column shows current org affiliation only — we do NOT project at that team's park.
Rates (K%, BB%, HR-BF) are park-stripped; MiLB stat lines are translated to their MLB-equivalent via per-level MLE factors.
WAR is computed from projected runs prevented vs a replacement pitcher (the marginal arm a team would call up if this pitcher were unavailable) — calibrated to industry-standard fWAR.

YearAge LvlTeam GGSIPBF KBBHR GS%IP/G K%BB%K-BB%HR% ERAFIP WAR
▸ Career — actual stats, one row per year (as recorded, no adjustments)
▸ Career — adjusted (each season translated to a park/league-neutral MLB-equivalent line; levels combined per year)
▸ Model inputs — neutral MLE (past 3 seasons + 2027 so far)
201921ROK MLEAZL Rangers10131000%1.033.3%0.0%33.3%0.0%0.000.29—
201921ROK RAWAZL Rangers10131000%1.033.3%0.0%33.3%0.0%0.001.10—
202123A+ MLEHickory Crawdads201982366110311795%4.123.1%9.7%13.4%6.6%6.016.00—
202123A+ RAWHickory Crawdads201982366110311795%4.130.1%8.5%21.6%4.6%6.014.24—
202224MIX MLE2 levels265522466648619%2.021.3%21.7%-0.4%3.2%6.795.83—
202224MIX RAW2 levels265522466648619%2.026.8%19.5%7.3%2.4%6.794.84—
202325MIX MLE2 levels401602358620102%1.530.3%8.7%21.7%5.5%2.874.63—
202325MIX RAW2 levels401602358620102%1.536.6%8.5%28.1%4.3%2.873.40—
202426MIX MLE2 levels45056227591040%1.225.9%4.0%21.9%1.8%3.072.43+1.4
202426MIX MLE2 levels45056227591040%1.225.9%4.0%21.9%1.8%3.072.43+1.4
202426MIX RAW2 levels45056227591040%1.226.0%4.4%21.6%1.8%3.072.45+1.4
202527MIX MLE2 levels3903714930930%0.918.2%5.8%12.4%2.2%3.893.53+0.4
202527MIX MLE2 levels3903714930930%0.918.2%5.8%12.4%2.2%3.893.53+0.4
202527MIX RAW2 levels3903714930930%0.920.1%6.0%14.1%2.0%3.893.26+0.6
202628MIX MLE3 levels3823314643945%0.928.5%5.8%22.6%3.0%4.323.08+0.6
202628MIX MLE3 levels3823314643945%0.928.5%5.8%22.6%3.0%4.323.08+0.6
202628MIX RAW3 levels3823314643945%0.929.5%6.2%23.3%2.7%4.322.89+0.7
▸ Career totals (raw MLB only — as recorded)
MLB Career—116012149812225110%1.024.5%5.0%19.5%2.2%3.732.88+2.4
▸ 2027 season — projected remainder (no 2027 stats recorded)
202729MLBBOS3303514839840%1.126.5%5.1%21.4%2.8%3.503.40+0.5
▸ Career projection (2028+) — MLB context, MLB playing time (IP × MLB%)
202830MLB MLEBOS52055231601270%1.125.8%5.4%20.4%3.0%3.563.60+0.6
202931MLB MLEBOS49051215541270%1.025.0%5.7%19.3%3.2%3.733.84+0.4
202830MLB CTXBOS50052220571260%1.025.8%5.4%20.4%3.0%3.563.60+0.6
202931MLB CTXBOS46048203511260%1.025.0%5.7%19.3%3.2%3.733.84+0.4
▸ Career totals — MLB only (actual + projected)
Career— RAW212022192223049240%1.024.9%5.3%19.7%2.6%3.693.09+3.9
/ 200 IP— RAW191020083420844220%1.024.9%5.3%19.7%2.6%3.693.09+3.5
Career— MLE2092732113723371365713%1.524.6%9.9%14.7%4.1%4.604.55+3.5
/ 200 IP— MLE13017200856210853513%1.524.6%9.9%14.7%4.1%4.604.55+3.1

Career Comps

Completed MLB careers (no pro action in 2+ yrs) whose totals — actual + projected — most resemble this player's. Pool: 1,474 reliever careers (754 from 1990-2025 + 720 historical, 1901-2023), also matched on career-to-date at the same age. * Historical (Lahman) careers: rates era-adjusted to 2001-24 league levels; WAR is an OGILVIE proxy.

Player162sIP/yrK%BB%HR/9ERA
OGILVIE CAREER PROJECTION1.34425.2%5.4%1.023.66
Nick Vincent ('21)2.14624.1%6.2%0.943.30
Junichi Tazawa ('18)2.04922.2%6.5%1.124.12
Héctor Rondón ('20)2.25424.2%7.4%1.033.49
Mike Schooler ('88-'93, 5 WAR*)1.54926.9%*8.0%*0.96*3.68*
Tim Crews ('87-'92, 3 WAR*)2.17120.8%*6.2%*1.09*4.11*
Steve Hamilton ('61-'72, 10 WAR*)3.36625.2%*7.7%*0.92*3.71*