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Justin Slaten

#63 - Relief Pitcher

Boston Red Sox

Bats / Throws Right / Right
Date of Birth 9/15/1997 (28)
Height, Weight 6'4", 222 lb
Hometown Longview, TX

2026 Season Stats

MLB Rank MLB Average
Sv IP ERA WHIP K% BB%
0 8.0 0.00 0.75 36.7% 6.7%
127th 1
Sv
301st 17.0
IP
1st 4.68
ERA
29th 1.45
WHIP
23rd 21.9%
K%
86th 10.7%
BB%
FB MPH SwStr% CSW% Str-ICR MTK% PLV PLA
97.1 12.3% 29.5% 55.7% 7.4% 5.13 2.61
41st 94.2
FB MPH
169th 11.9%
SwStr%
178th 28.5%
CSW%
61st 50.2%
Str-ICR
338th 4.5%
MTK%
64th 4.93
PLV
66th 3.65
PLA
Holds List
Rank
19th
Saves+Holds List
Rank
41st

Articles

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5/18/2026Relief Pitcher Streamer Rankings Fantasy Baseball: 5/18Rick Graham

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See More Articles
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Justin Slaten Overview

Hide 2026 MLB Percentile | Hide 2026 MLB Average
Year Team G GS IP W-L Sv Hld ERA WHIP xERA FIP xFIP PLA K% BB% H/9 HR/9 BABIP HR/FB% LOB% ICR GB% SwStr% CSW% IPR PLV
2024 BOS 44 0 55.1 6-2 2 13 2.93 1.01 2.77 2.60 2.96 2.67 25.9% 4.0% 7.6 0.65 .285 13.3% 70.6% 38.1% 50.6% 15.5% 29.3% 0.55 5.12
2025 BOS 36 0 34.0 2-4 3 7 4.24 1.09 3.30 3.69 4.34 2.41 18.2% 7.3% 7.1 0.79 .242 12.0% 54.9% 36.3% 43.1% 15.0% 27.9% 0.48 5.19
2026 BOS 9 0 8.0 0-1 0 5 0.00 0.75 1.12 1.11 2.53 2.61 36.7% 6.7% 4.5 0.00 .235 0.0% 83.3% 35.3% 47.1% 12.3% 29.5% 0.62 5.13
RP MLB Percentile 24 0 14 0-23 0 74 98 91 99 97 87 81 93 75 87 78 67 78 78 51 43 51 49 76 80
RP MLB AVG 14 1 17.0 1-1 1 2 4.68 1.45 4.43 4.44 4.45 3.65 21.9% 10.7% 8.7 1.07 .295 17.1% 71.3% 37.5% 44.7% 11.9% 28.5% 0.49 4.93
Career 89 0 97.1 8-7 5 25 3.14 1.02 2.82 2.86 3.41 2.58 24.0% 5.4% 7.2 0.65 .266 11.7% 65.8% 37.2% 47.6% 15.1% 28.8% 0.53 5.15

Justin Slaten Repertoire

2024 2025 2026 All
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Justin Slaten Game Log

Justin Slaten Standard

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Year Team G GS IP W-L QS Sv Hld P Strikes Balls TBF H 1B 2B 3B HR K BB HB WP
2024 BOS 44 0 55.1 6-2 0 2 13 811 546 265 224 47 36 6 1 4 58 9 2 4
2025 BOS 36 0 34.0 2-4 0 3 7 499 333 166 137 27 21 3 0 3 25 10 0 1
2026 BOS 9 0 8.0 0-1 0 0 5 122 80 42 30 4 4 0 0 0 11 2 0 0
RP MLB Percentile 24 0 14 0-23 0 0 74 12 13 91 11 94 82 89 21 78 22 91 55 46
RP MLB AVG 14 1 17.0 1-1 0 1 2 296 187 109 76 16 11 3 0 2 17 8 1 1
Career 89 0 97.1 8-7 0 5 25 1,432 959 473 391 78 61 9 1 7 94 21 2 5

Justin Slaten Advanced

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Year Team K% BB% AVG SLG OPS wOBA BABIP BACON xAVG xwOBA xBABIP xwoBACON EV FB EV LA xERA
2024 BOS 25.9% 4.0% .223 .318 .577 .253 .285 .303 .214 .259 .264 .326 87.6 89.4 8.9 2.77
2025 BOS 18.2% 7.3% .214 .310 .580 .251 .242 .265 .231 .278 .261 .314 89.1 92.3 12.3 3.30
2026 BOS 36.7% 6.7% .143 .143 .343 .167 .235 .235 .140 .168 .231 .214 89.4 88.7 6.4 1.12
RP MLB Percentile 93 75 88 98 98 97 67 80 96 99 79 97 14 59 79 99
RP MLB AVG 21.9% 10.7% .244 .389 .723 .323 .295 .323 .238 .324 .284 .363 88.1 89.3 12.9 4.43
Career 24.0% 5.4% .214 .301 .559 .251 .266 .285 .214 .264 .261 .320 88.3 90.5 10.0 2.82

Justin Slaten Pitch › Mix

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Year Team FF% (MPH) SI% (MPH) FC% (MPH) SL% (MPH) ST% (MPH) CB% (MPH) CH% (MPH) FS% (MPH) KN% (MPH) Fastball% Secondary%
2024 BOS 29.2% (96.4) - 37.7% (91.5) - 24.5% (84.0) 8.4% (84.3) - - - 29.2% 70.7%
2025 BOS 36.1% (96.7) - 34.5% (92.7) - 11.4% (85.1) 18.0% (84.9) - - - 36.1% 63.9%
2026 BOS 27.9% (97.1) - 53.3% (92.7) - 16.4% (85.9) 2.5% (85.1) - - - 27.9% 72.1%
RP MLB Percentile 36 (87) - 98 (92) - 36 (88) 2 (87) - - - 10.8% 88.6%
RP MLB AVG 35.7% (94.2) 26.7% (93.8) 20.5% (89.3) 26.8% (85.4) 22.9% (82.5) 17.4% (80.4) 18.5% (86.1) 19.8% (86.3) 31.8% (68.1) 47.9% 52.0%
Career 31.5% (96.6) - 37.9% (92.0) - 19.3% (-) 11.2% (84.6) - - - 31.5% 68.4%

Justin Slaten Pitch › Results

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Year Team FF CSW% SI CSW% FC CSW% SL CSW% ST CSW% CB CSW% CH CSW% FS CSW% KN CSW% Fastball CSW% Secondary CSW%
2024 BOS 29.1% (33) - 29.4% (40) - 28.6% (42) 32.4% (11) - - - 29.1% 29.5%
2025 BOS 26.1% (28) - 33.1% (19) - 28.1% (13) 21.1% (15) - - - 26.1% 28.8%
2026 BOS 23.5% (5) - 30.8% (5) - 30.0% (5) 66.7% (0) - - - 23.5% 31.8%
RP MLB Percentile 30 (57) - 67 (41) - 60 (52) 99 (0) - - - 11.4% 70.5%
RP MLB AVG 26.6% (9) 27.9% (5) 27.1% (6) 29.9% (10) 27.7% (9) 26.8% (6) 22.2% (8) 25.5% (10) 23.3% (6) 28.0% 28.4%
Career 27.5% (66) - 30.8% (64) - 28.6% (60) 26.7% (26) - - - 27.5% 29.5%

Justin Slaten Batted Ball › Contact

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Year Team GB% LD% FB% PU% SS% Pull% Cent% Oppo% Foul Str% PC% Fl&B% Solid% Brl% ICR
2024 BOS 50.6% 20.8% 19.5% 9.1% 31.2% 44.2% 35.7% 20.1% 18.9% 61.6% 27.3% 7.1% 3.9% 38.1%
2025 BOS 43.1% 21.6% 24.5% 10.8% 33.3% 36.3% 42.2% 21.6% 18.4% 63.8% 21.6% 8.8% 5.9% 36.3%
2026 BOS 47.1% 23.5% 29.4% 0.0% 35.3% 58.8% 29.4% 11.8% 22.1% 64.7% 29.4% 5.9% 0.0% 35.3%
RP MLB Percentile 43 30 82 0 34 99 36 1 95 54 15 42 90 51
RP MLB AVG 44.7% 21.3% 23.9% 10.1% 34.1% 41.4% 33.9% 24.7% 17.4% 62.2% 24.4% 6.1% 7.3% 37.5%
Career 47.6% 21.2% 22.0% 9.2% 32.2% 42.1% 37.7% 20.1% 19.0% 62.7% 25.3% 7.7% 4.4% 37.2%

Justin Slaten Batted Ball › Outcomes

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Year Team AVG wOBA BABIP BACON xAVG xwOBA xBABIP xwoBACON EV FB EV LA HR/FB ICR IPA%
2024 BOS .223 .253 .285 .303 .214 .259 .264 .326 87.6 89.4 8.9 13.3% 38.1% 26.3%
2025 BOS .214 .251 .242 .265 .231 .278 .261 .314 89.1 92.3 12.3 12.0% 36.3% 27.0%
2026 BOS .143 .167 .235 .235 .140 .168 .231 .214 89.4 88.7 6.4 0.0% 35.3% 20.0%
RP MLB Percentile 88 97 67 80 96 99 79 97 14 59 79 78 51 68
RP MLB AVG .244 .323 .295 .323 .238 .324 .284 .363 88.1 89.3 12.9 17.1% 37.5% 24.7%
Career .214 .251 .266 .285 .214 .264 .261 .320 88.3 90.5 10.0 11.7% 37.2% 26.1%

Justin Slaten Approach › Plate Discipline

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Year Team Zone% Str% Swing% O-Sw% Whiff% Foul Str% Con% Z-Con% O-Con% CS% SwStr% CSW% BIP% PLUS% IPR Str-ICR
2024 BOS 46.6% 67.3% 53.5% 37.0% 29.0% 18.9% 71.0% 85.4% 46.3% 13.8% 15.5% 29.3% 19.1% 61.5% 0.55 52.8%
2025 BOS 49.7% 66.7% 53.9% 33.9% 27.9% 18.4% 72.1% 79.9% 55.3% 12.8% 15.0% 27.9% 20.4% 61.3% 0.48 51.9%
2026 BOS 55.7% 65.6% 48.4% 24.1% 25.4% 22.1% 74.6% 82.6% 46.2% 17.2% 12.3% 29.5% 13.9% 62.3% 0.62 55.7%
RP MLB Percentile 98 74 73 13 42 95 42 57 78 48 51 49 15 87 76 82
RP MLB AVG 44.3% 63.0% 46.4% 30.6% 25.5% 17.4% 74.5% 84.0% 58.6% 16.6% 11.9% 28.5% 17.0% 57.5% 0.49 50.2%
Career 48.5% 67.0% 53.2% 35.0% 28.3% 19.0% 71.7% 83.1% 49.2% 13.8% 15.1% 28.8% 19.1% 61.5% 0.53 52.7%

Justin Slaten Approach › Locations

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Year Team Zone% aLoc% x-mLoc% gLoc% hiLoc% y-mLoc% loLoc% iLoc% oLoc% mmLoc%
2024 BOS 46.6% 22.5% 33.1% 44.4% 32.5% 19.1% 48.4% 29.8% 37.2% 6.2%
2025 BOS 49.7% 22.2% 32.5% 45.3% 30.7% 20.4% 48.9% 31.1% 36.5% 7.2%
2026 BOS 55.7% 21.3% 34.4% 44.3% 38.5% 18.0% 43.4% 29.5% 36.1% 9.0%
RP MLB Percentile 98 1 3 90 51 75 65 61 9 95
RP MLB AVG 44.3% 34.9% 26.7% 38.3% 36.1% 22.9% 41.0% 30.6% 42.7% 6.4%
Career 48.5% 22.3% 33.0% 44.7% 32.4% 19.5% 48.1% 30.2% 36.8% 6.8%

Justin Slaten Approach › Counts

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Year Team Early% Behind% 2-Str% Early BIP% F-Str% TF-Str% ECS% 2-Str O-Sw% PAR%
2024 BOS 60.9% 10.5% 28.7% 18.0% 63.4% 48.2% 17.2% 26.6% 24.9%
2025 BOS 61.5% 12.2% 27.3% 16.0% 61.0% 45.6% 16.0% 28.7% 18.4%
2026 BOS 55.7% 13.9% 30.3% 14.7% 73.3% 63.3% 22.1% 16.2% 29.7%
RP MLB Percentile 8 20 57 60 95 92 40 5 91
RP MLB AVG 58.6% 12.8% 29.2% 14.3% 60.1% 49.5% 21.1% 26.0% 19.2%
Career 60.7% 11.4% 28.4% 17.0% 63.3% 48.5% 17.1% 26.4% 23.2%

Justin Slaten PLV

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Year Team P PLV QP% AP% BP% Q-BP% MTK% HP HL PLA
2024 BOS 811 5.12 47.1% 19.1% 33.8% 13.3% 4.8% -3.8 +10 2.67
2025 BOS 499 5.19 49.5% 18.0% 32.5% 17.0% 4.2% -1.2 +3 2.41
2026 BOS 122 5.13 49.2% 18.9% 32.0% 17.2% 7.4% -3.6 -4 2.61
RP MLB Percentile 12 80 66 85 86 86 3 80 83 81
RP MLB AVG 296 4.93 46.1% 16.9% 37.0% 9.2% 4.5% 0.5 +0 3.65
Career 1,432 5.15 48.1% 18.7% 33.2% 14.9% 4.8% -8.6 +9 2.58
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