Justin Slaten

Justin Slaten

27-Year-Old PitcherRP
Boston Red Sox
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
RANKS
From Preseason
$Signed a one-year contract with the Red Sox in March of 2024.
Notches second save
PBoston Red Sox
September 29, 2024
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
Slaten allowed a bunt single to Dylan Carlson to lead off the ninth but otherwise had no trouble wrapping things up. With incumbent closer Kenley Jansen on the injured list, Slaten was able to notch his first save since March 31. The 27-year-old Slaten had an encouraging rookie season out of the Red Sox bullpen, pitching to a 2.93 ERA, 1.01 WHIP and 58:9 K:BB in 55.1 innings with six wins, 13 holds and two saves. The 37-year-old Jansen is set to become a free agent, so Slaten could find himself in the mix for saves next season.
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Pitching Stats
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2024
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Pitching Appearances Breakdown
Average Pitch Count
18
Last 10 Games
14
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+
 
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+
 
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
 
 
 
1st
 
 
 
2nd
 
 
 
3rd
 
 
 
4th
 
 
 
5th
 
 
 
6th
 
 
 
7th
 
 
 
8th
 
 
 
9th
 
Extra
 
 
 
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 2022
 
 
-25%
BAA vs LHP
2024
 
 
-25%
BAA vs LHP
2023
No Stats
2022
No Stats
BAA Batters K BB H 2B 3B HR
Since 2022vs Left .188 105 31 8 18 4 0 2
Since 2022vs Right .252 119 27 1 29 2 1 2
2024vs Left .188 105 31 8 18 4 0 2
2024vs Right .252 119 27 1 29 2 1 2
2023vs Left 0 0 0 0 0 0 0 0
2023vs Right 0 0 0 0 0 0 0 0
2022vs Left 0 0 0 0 0 0 0 0
2022vs Right 0 0 0 0 0 0 0 0
More Splits View More Split Stats
Home/Away Pitching Splits
Since 2022
 
 
-54%
ERA at Home
2024
 
 
-54%
ERA at Home
2023
No Stats
2022
No Stats
ERA WHIP IP W L SV K/9 BB/9 HR/9
Since 2022Home 1.78 0.87 25.1 3 0 1 8.5 1.4 0.7
Since 2022Away 3.90 1.13 30.0 3 2 1 10.2 1.5 0.6
2024Home 1.78 0.87 25.1 3 0 1 8.5 1.4 0.7
2024Away 3.90 1.13 30.0 3 2 1 10.2 1.5 0.6
2023Home 0 0 0 0 0 0 0 0 0
2023Away 0 0 0 0 0 0 0 0 0
2022Home 0 0 0 0 0 0 0 0 0
2022Away 0 0 0 0 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.
  • K/BB
    Strikeout to walk ratio.
  • K/9
    Average strikeouts per nine innings.
  • BB/9
    Average walks per nine innings.
  • HR/9
    Average home runs allowed per nine innings.
  • Fastball
    Average fastball velocity.
  • ERA
    Earned run average. The average earned runs allowed per nine innings.
  • WHIP
    Walks plus hits per inning pitched.
  • BABIP
    Batting average on balls in play. Measures how many balls in play against a pitcher go for hits.
  • GB/FB
    Groundball to flyball ratio. The higher the number, the more likely a pitcher is to induce groundballs.
  • Left On Base
    The percentage of base runners that a pitcher strands on base over the course of a season.
  • Exit Velocity
    The speed of the baseball as it comes off the bat, immediately after a batter makes contact.
  • Barrels/BBE
    The percentage of batted ball events resulting in a Barrel. A Barrel is a batted ball with similar exit velocity and launch angle to past ones that led to a minimum .500 batting average and 1.500 slugging percentage.
  • Spin Rate
    Spin Rate is the rate of spin on a baseball after it is released. It is measured in revolutions per minute (rpm).
  • Balls Hit 95+ MPH
    The percentage of batted balls hit that met or exceeded the 95 MPH threshold.
  • Swinging Strike
    The percentage of pitches that result in a swing and a miss.
K/BB
6.44
 
K/9
9.4
 
BB/9
1.5
 
HR/9
0.7
 
Fastball
96.5 mph
 
ERA
2.93
 
WHIP
1.01
 
BABIP
.305
 
GB/FB
1.86
 
Left On Base
69.4%
 
Exit Velocity
81.7 mph
 
Barrels/BBE
2.7%
 
Spin Rate
2471 rpm
 
Balls Hit 95+ MPH
22.6%
 
Swinging Strike
14.7%
 
Advanced Pitching Stats
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Defensive Stats
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Stats Vs Today's Lineup
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More Fantasy News
Candidate for saves
PBoston Red Sox
September 23, 2024
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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Returns to mound Monday
PBoston Red Sox
August 27, 2024
Slaten struck out one over a scoreless inning in the second game of Monday's doubleheader against Toronto.
ANALYSIS
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Returns from IL
PBoston Red Sox
August 26, 2024
The Red Sox activated Slaten (elbow) from the 15-day injured list Monday, Jen McCaffrey of The Athletic reports.
ANALYSIS
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Throws bullpen Sunday
PBoston Red Sox
Elbow
August 26, 2024
Slaten threw a bullpen session prior to Sunday's game against the Diamondbacks, Jen McCaffrey of The Athletic reports.
ANALYSIS
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Might need another outing
PBoston Red Sox
Elbow
August 25, 2024
Boston manager Alex Cora was non-committal Saturday when asked if one rehab outing would be enough for Slaten (elbow) before returning from the 15-day injured list, MLB.com reports.
ANALYSIS
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