2025 Stats
W-L
0-0
ERA
0.00
WHIP
0.50
K
2
SV
0
Rest-of-Season Projections

Reinstated from IL
The Mariners reinstated Kowar (elbow) from the 60-day injured list Wednesday.
ANALYSIS
Kowar will return to the majors after missing the entire 2024 season following Tommy John surgery last March. The 28-year-old right hander posted a 2.57 ERA and 1.29 WHIP across seven innings during his rehab assignment and did not yield a run in each of his last three outings. Kowar will be available to make his 2025 debut out of the Mariners' bullpen against the Nationals on Wednesday. Logan Evans was optioned to Triple-A Tacoma in a corresponding move.
Kowar will return to the majors after missing the entire 2024 season following Tommy John surgery last March. The 28-year-old right hander posted a 2.57 ERA and 1.29 WHIP across seven innings during his rehab assignment and did not yield a run in each of his last three outings. Kowar will be available to make his 2025 debut out of the Mariners' bullpen against the Nationals on Wednesday. Logan Evans was optioned to Triple-A Tacoma in a corresponding move.
Pitching Stats
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2025
2024
2023
2022
2021
Minor League Game Log

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Pitching Appearances Breakdown
Average Pitch Count
20
Last 10 Games
20
Last 5 Games
20
How many pitches does Jackson Kowar 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 Jackson Kowar 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
-1%
BAA vs RHP
2025
-100%
BAA vs RHP
BAA | K | BB | H | HR | ||||
---|---|---|---|---|---|---|---|---|
Since 2023vs Left | .281 | 10 | 7 | 16 | 1 | |||
Since 2023vs Right | .278 | 21 | 13 | 20 | 3 | |||
2025vs Left | .182 | 1 | 0 | 2 | 0 | |||
2025vs Right | .000 | 1 | 0 | 0 | 0 | |||
2024vs Left | 0 | 0 | 0 | 0 | 0 | |||
2024vs Right | 0 | 0 | 0 | 0 | 0 | |||
2023vs Left | .304 | 9 | 7 | 14 | 1 | |||
2023vs Right | .286 | 20 | 13 | 20 | 3 | |||
More Splits→ | View More Split Stats |
Home/Away Pitching Splits
Since 2023
-83%
ERA at Home
2025
No Stats
ERA | WHIP | IP | K/9 | BB/9 | |||||
---|---|---|---|---|---|---|---|---|---|
Since 2023Home | 1.65 | 0.92 | 16.1 | 9.4 | 2.2 | ||||
Since 2023Away | 9.77 | 2.62 | 15.2 | 8.0 | 9.2 | ||||
2025Home | 0.00 | 0.50 | 4.0 | 4.5 | 0.0 | ||||
2025Away | 0 | 0 | 0 | 0 | 0 | ||||
2024Home | 0 | 0 | 0 | 0 | 0 | ||||
2024Away | 0 | 0 | 0 | 0 | 0 | ||||
2023Home | 2.19 | 1.05 | 12.1 | 10.9 | 2.9 | ||||
2023Away | 9.77 | 2.62 | 15.2 | 8.0 | 9.2 | ||||
More Splits→ | View More Split Stats |
Stat Review
How does Jackson Kowar 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
0.00K/9
4.5BB/9
0.0HR/9
0.0Fastball
97.7 mphERA
0.00WHIP
0.50BABIP
.177GB/FB
0.43Left On Base
100.0%Exit Velocity
81.6 mphBarrels/BBE
0.0%Spin Rate
2289 rpmBalls Hit 95+ MPH
16.7%Swinging Strike
9.8%Prospect Rankings History
Advanced Pitching Stats
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Defensive Stats
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Stats Vs Today's Lineup
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Past Fantasy Outlooks
2023
2021
2020
An ugly 2022 campaign took a lot of shine out of Kowar's prospect stock. He worked as a starter with Triple-A Omaha, but a 6.16 ERA and 1.66 WHIP over 83.1 innings at that level easily made his worst minor-league season. Despite the struggles, he also made seven relief appearances in the majors, and the results were even worse -- a 9.77 ERA and 2.43 WHIP across 15.2 innings. With 46 big-league innings to his name in the majors, it's too early to write off the right-hander, but it's fair to question if his stuff is good enough. His 96 mph fastball didn't miss many bats, though he uses a very effective changeup almost as often, with that pitch racking up a 35 whiff rate in the majors. He'll likely be in the minors or in the rotation in 2023, as the Royals will probably want to give him one more chance to prove himself as a starter, but he's got work to do.
More Fantasy News

Closing in on return
Kowar (elbow) could be nearing his activation from the 60-day injured list, MLB.com reports.
ANALYSIS
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Moves to 60-day IL
Kowar (elbow) was placed on the 60-day injured list Sunday, Daniel Kramer of MLB.com reports.
ANALYSIS
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Completes bullpen session
Kowar (elbow) threw a bullpen session Monday, Ryan Divish of The Seattle Times reports.
ANALYSIS
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Requires Tommy John surgery
The Mariners placed Kowar on the 60-day injured list Sunday after he was diagnosed with a torn UCL in his right elbow. He'll undergo Tommy John surgery next Friday in Dallas, Daniel Kramer of MLB.com reports.
ANALYSIS
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Getting sore arm checked out
Kowar will meet with a doctor Friday to have his sore right arm examined, Ryan Divish of The Seattle Times reports.
ANALYSIS
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Latest Fantasy Rumors

Will switch to bullpen
Kowar is expected to come out of the bullpen going forward, Jaylon Thompson of the Kansas City Star.
ANALYSIS
Kowar has been tabbed as a top pitching prospect since being selected with the 33rd overall pick in the 2018 MLB Draft, but he hasn't panned out as a starter to this point, and now the Royals have decided to take a look at him as a relief option. He's made 12 of his 13 Triple-A appearances out of the bullpen, and the results haven't been encouraging. The 26-year-old has posted a 7.00 ERA with 22 strikeouts and 15 walks across 18 relief innings. However, the organization still rates him highly, and manager Matt Quatraro told Thompson earlier this week that the Royals see Kowar as "someone we can count on going forward."
Kowar has been tabbed as a top pitching prospect since being selected with the 33rd overall pick in the 2018 MLB Draft, but he hasn't panned out as a starter to this point, and now the Royals have decided to take a look at him as a relief option. He's made 12 of his 13 Triple-A appearances out of the bullpen, and the results haven't been encouraging. The 26-year-old has posted a 7.00 ERA with 22 strikeouts and 15 walks across 18 relief innings. However, the organization still rates him highly, and manager Matt Quatraro told Thompson earlier this week that the Royals see Kowar as "someone we can count on going forward."