2025 Stats
W-L
0-0
ERA
4.00
WHIP
0.56
K
8
SV
3
Rest-of-Season Projections
2025 Fantasy Outlook
Slaten, a 2019 draft pick by the Rangers, was selected by the Mets during the Rule 5 Draft last offseason. The 26-year-old was subsequently traded to Boston and impressed his new club during Grapefruit League play, flashing upper-90's velocity. Unsurprisingly, he made the Red Sox Opening Day roster and remained with the team all year. Slaten was an immediate fixture in Boston's high-leverage hierarchy, mixing four pitches effectively to a 2.93 ERA, 1.01 WHIP and 58:9 K:BB across 55.1 frames. The rookie right-hander recorded 10 or more strikeouts on all four of his offerings, including 18 apiece on his four-seamer and sweeper. Elbow inflammation cost Slaten a month-and-a-half last summer, but it's exciting to think about what he could offer in a full season. Red Sox manager Alex Cora said in the past that he envisions Slaten as a potential long-term closer option and he certainly has the talent to emerge out of a save share with Liam Hendriks and Aroldis Chapman in 2025. Read Past Outlooks
Notches third save
Slaten picked up the save in Monday's 4-2 win against the White Sox, pitching a clean inning with one strikeout.
ANALYSIS
Slaten efficiently secured the win, requiring only 12 pitches -- 10 of which were strikes -- to retire the side in order. Aroldis Chapman pitched the eighth inning, as he was called upon to face the top of the Chicago lineup. However, this outing shows that Slaten could be in line for more save opportunities as Boston manager Alex Cora may look to deploy Chapman in the highest leverage spots. Although Slaten owns a 4.00 ERA, his performance has been much better under the hood, pitching to a 1.59 FIP, 0.56 WHIP and 8:1 K:BB across nine innings.
Slaten efficiently secured the win, requiring only 12 pitches -- 10 of which were strikes -- to retire the side in order. Aroldis Chapman pitched the eighth inning, as he was called upon to face the top of the Chicago lineup. However, this outing shows that Slaten could be in line for more save opportunities as Boston manager Alex Cora may look to deploy Chapman in the highest leverage spots. Although Slaten owns a 4.00 ERA, his performance has been much better under the hood, pitching to a 1.59 FIP, 0.56 WHIP and 8:1 K:BB across nine innings.
Pitching Stats
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2025
2024
Minor League Game Log
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Pitching Appearances Breakdown
Average Pitch Count
11
Last 10 Games
11
Last 5 Games
11
How many pitches does Justin Slaten generally throw?
1-10
11-20
21-30
31-40
41-50
51-60
61-70
71-80
81-90
91-100
101-110
111-120
121+
What part of the game does Justin Slaten generally pitch?
1st
2nd
3rd
4th
5th
6th
7th
8th
9th
Extra
% Games Reaching Innings Threshold
% Games By Number of Innings Pitched
Left/Right Pitching Splits
Since 2023
-26%
BAA vs LHP
2025
-47%
BAA vs LHP
| BAA | K | BB | H | HR | ||||
|---|---|---|---|---|---|---|---|---|
| Since 2023vs Left | .176 | 34 | 9 | 19 | 2 | |||
| Since 2023vs Right | .239 | 32 | 1 | 32 | 2 | |||
| 2025vs Left | .083 | 3 | 1 | 1 | 0 | |||
| 2025vs Right | .158 | 5 | 0 | 3 | 0 | |||
| 2024vs Left | .188 | 31 | 8 | 18 | 2 | |||
| 2024vs Right | .252 | 27 | 1 | 29 | 2 | |||
| 2023vs Left | 0 | 0 | 0 | 0 | 0 | |||
| 2023vs Right | 0 | 0 | 0 | 0 | 0 | |||
| More Splits→ | View More Split Stats | |||||||
Home/Away Pitching Splits
Since 2023
-65%
ERA at Home
2025
-100%
ERA at Home
| ERA | WHIP | IP | K/9 | BB/9 | |||||
|---|---|---|---|---|---|---|---|---|---|
| Since 2023Home | 1.53 | 0.75 | 29.1 | 8.6 | 1.2 | ||||
| Since 2023Away | 4.37 | 1.11 | 35.0 | 9.8 | 1.5 | ||||
| 2025Home | 0.00 | 0.00 | 4.0 | 9.0 | 0.0 | ||||
| 2025Away | 7.20 | 1.00 | 5.0 | 7.2 | 1.8 | ||||
| 2024Home | 1.78 | 0.87 | 25.1 | 8.5 | 1.4 | ||||
| 2024Away | 3.90 | 1.13 | 30.0 | 10.2 | 1.5 | ||||
| 2023Home | 0 | 0 | 0 | 0 | 0 | ||||
| 2023Away | 0 | 0 | 0 | 0 | 0 | ||||
| More Splits→ | View More Split Stats | ||||||||
Stat Review
How does Justin Slaten compare to other relievers?
This section compares his stats with all relief pitcher seasons from the previous three seasons (minimum 30 innings)*. The bar represents the player's percentile rank. For example, if the bar is halfway across, then the player falls into the 50th percentile for that stat and it would be considered average.
* Exit Velocity, Barrels/BBE %, Balls Hit 95+ MPH %, and Spin Rate are benchmarked against 2019 data (min 30 IP). See here for more exit velocity/barrels stats plus an explanation of current limitations with that data set.
* Exit Velocity, Barrels/BBE %, Balls Hit 95+ MPH %, and Spin Rate are benchmarked against 2019 data (min 30 IP). See here for more exit velocity/barrels stats plus an explanation of current limitations with that data set.
K/BB
8.00K/9
8.0BB/9
1.0HR/9
0.0Fastball
97.0 mphERA
4.00WHIP
0.56BABIP
.187GB/FB
0.55Left On Base
20.0%Exit Velocity
83.5 mphBarrels/BBE
2.9%Spin Rate
2502 rpmBalls Hit 95+ MPH
11.4%Swinging Strike
16.8%Advanced Pitching Stats
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Defensive Stats
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Stats Vs Today's Lineup
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Recent RotoWire Articles Featuring Justin Slaten See More
A wave of top prospects joins the American League free-agent pool this week, including the Minnesota Twins' Luke Keaschall.
Brad Johnson dives deep into some bullpens in flux, including in Detroit where injured closer Alex Lange needs to work on finding the strike zone once he's back on the mound.
The American League free-agent pool features a lot of targets after the first full weekend of the season including top Red Sox prospect Kristian Campbell, who looks like he's in Boston to stay.
The American League waiver wire is packed with options as Opening Day approaches, and the return of Nolan Jones to the Cleveland Guardians should settle their murky right field situation.
Mason Miller makes a big jump in Ryan Rufe's updated closer rankings.
More Fantasy News
Slams door for second save
Slaten earned the save after throwing a clean ninth inning in Wednesday's win over the Rays. He struck out two.
ANALYSIS
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Notches save in opener
Slaten struck out one and didn't allow a baserunner in a scoreless ninth inning to earn the save Thursday against the Rangers.
ANALYSIS
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Works scoreless inning
Slaten allowed a hit and struck out two over a scoreless inning in Friday's spring game against Miami.
ANALYSIS
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Notches second save
Slaten allowed one hit and zero walks in a scoreless ninth inning to pick up his second save of the season in Sunday's season finale against Tampa Bay.
ANALYSIS
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Candidate for saves
Red Sox manager Alex Cora said Sunday that he will "mix and match" at closer with Slaten and Chris Martin following the season-ending injury to Kenley Jansen (shoulder), Gabrielle Starr of the Boston Herald reports.
ANALYSIS
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