2025 Stats
W-L
1-3
ERA
5.40
WHIP
1.07
K
9
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
Blows save, takes loss Thursday
Slaten (0-2) was charged with the loss and a blown save in Thursday's 4-2 defeat to the Blue Jays, allowing three runs on three hits and one walk with no strikeouts in one inning.
ANALYSIS
One game after giving up the game-ending run, albeit one that was unearned in extra innings, Slaten's showing Thursday was far less excusable. The right-hander gave up a go-ahead three-run home run to Vladimir Guerrero in the eighth inning, taking his first blown save of the season. Slaten now holds a 5.56 ERA, 1.15 WHIP and 9:5 K:BB over 11.1 innings this season, though he's been charged with an earned run in just two of his 13 outings.
One game after giving up the game-ending run, albeit one that was unearned in extra innings, Slaten's showing Thursday was far less excusable. The right-hander gave up a go-ahead three-run home run to Vladimir Guerrero in the eighth inning, taking his first blown save of the season. Slaten now holds a 5.56 ERA, 1.15 WHIP and 9:5 K:BB over 11.1 innings this season, though he's been charged with an earned run in just two of his 13 outings.
Pitching Stats
Loading Pitching Stats...
2025
2024
Minor League Game Log
Calculate Stats Over Time
Just click on any two dates.
Loading Minor League Pitching Game Log...
Pitching Appearances Breakdown
Average Pitch Count
14
Last 10 Games
15
Last 5 Games
17
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
-30%
BAA vs LHP
2025
-46%
BAA vs LHP
| BAA | K | BB | H | HR | ||||
|---|---|---|---|---|---|---|---|---|
| Since 2023vs Left | .176 | 35 | 12 | 21 | 2 | |||
| Since 2023vs Right | .250 | 32 | 2 | 37 | 3 | |||
| 2025vs Left | .130 | 4 | 4 | 3 | 0 | |||
| 2025vs Right | .242 | 5 | 1 | 8 | 1 | |||
| 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
-57%
ERA at Home
2025
-61%
ERA at Home
| ERA | WHIP | IP | K/9 | BB/9 | |||||
|---|---|---|---|---|---|---|---|---|---|
| Since 2023Home | 1.99 | 0.79 | 31.2 | 8.0 | 1.1 | ||||
| Since 2023Away | 4.66 | 1.22 | 38.2 | 9.1 | 2.3 | ||||
| 2025Home | 2.84 | 0.47 | 6.1 | 5.7 | 0.0 | ||||
| 2025Away | 7.27 | 1.50 | 8.2 | 5.2 | 5.2 | ||||
| 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
1.80K/9
5.4BB/9
3.0HR/9
0.6Fastball
97.1 mphERA
5.40WHIP
1.07BABIP
.231GB/FB
0.55Left On Base
41.1%Exit Velocity
84.4 mphBarrels/BBE
5.9%Spin Rate
2531 rpmBalls Hit 95+ MPH
19.1%Swinging Strike
12.1%Advanced Pitching Stats
Loading Advanced Pitching Stats...
Defensive Stats
Loading MLB Defensive Stats...
Stats Vs Today's Lineup
Want more matchup stats?
Loading Matchup Stats...
Our full team depth charts are reserved for RotoWire subscribers.
Subscribe Now
Recent RotoWire Articles Featuring Justin Slaten See More
James Anderson provides the top relief pitching prospects for your dynasty leagues on all 30 teams, plus the top reliever prospects to add in dynasty leagues, led by Rays lefty Mason Montgomery!
Check out the top AL fantasy baseball waiver wire pickups and FAAB targets for this week. Get expert advice to stay ahead in your fantasy baseball league.
Discover Thursday's top FAAB targets including a plethora of prospects like the A's first baseman Nick Kurtz.
Brad Johnson covers early-in-the-season standout fantasy baseball pitchers, featuring Nick Lodolo, Tyler Mahle and more.
A wave of top prospects joins the American League free-agent pool this week, including the Minnesota Twins' Luke Keaschall.
More Fantasy News
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
Subscribe now to instantly reveal our take on this news.
Subscribe now to instantly reveal our take on this 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
Subscribe now to instantly reveal our take on this news.
Subscribe now to instantly reveal our take on this news.
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
Subscribe now to instantly reveal our take on this news.
Subscribe now to instantly reveal our take on this news.
Works scoreless inning
Slaten allowed a hit and struck out two over a scoreless inning in Friday's spring game against Miami.
ANALYSIS
Subscribe now to instantly reveal our take on this news.
Subscribe now to instantly reveal our take on this news.
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
Subscribe now to instantly reveal our take on this news.
Subscribe now to instantly reveal our take on this news.