15-Day IL
                                            Injury Shoulder
                                                Est. Return 2/1/2026
                                        2025 Stats
                    W-L
                                2-0
                            ERA
                                4.24
                            WHIP
                                1.24
                            K
                                15
                            SV
                                0
                            Rest-of-Season Projections
                    
                 
                  Option reversed, lands on IL
The Mariners recalled Kowar from Triple-A Tacoma and placed him on the 15-day injured list Wednesday with a right shoulder impingement, retroactive to Aug. 19.
                  Analysis
Kowar was sent down to Triple-A in mid-August but hasn't pitched for Tacoma since being demoted. Now dealing with a shoulder issue, the 28-year-old will return to the big-league club to rehab his injury. He'll be eligible to return from the IL as soon as he's healthy, but there's currently no telling how close he is to activation.
              Kowar was sent down to Triple-A in mid-August but hasn't pitched for Tacoma since being demoted. Now dealing with a shoulder issue, the 28-year-old will return to the big-league club to rehab his injury. He'll be eligible to return from the IL as soon as he's healthy, but there's currently no telling how close he is to activation.
Pitching Stats
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2025 MLB Game Log
        2025
				2024
				2023
				2022
				2021
		        Minor League Game Log
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Pitching Appearances Breakdown
        Average Pitch Count
                        19
                    Last 10 Games
                        17
                    Last 5 Games
                        16
                    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
                                    -6%
                        BAA vs LHP
                    2025
                                    -18%
                        BAA vs LHP
                    | BAA | K | BB | H | HR | ||||
|---|---|---|---|---|---|---|---|---|
| Since 2023vs Left | .259 | 18 | 10 | 22 | 3 | |||
| Since 2023vs Right | .277 | 26 | 17 | 26 | 5 | |||
| 2025vs Left | .205 | 9 | 3 | 8 | 2 | |||
| 2025vs Right | .250 | 6 | 4 | 6 | 2 | |||
| 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
                                    -71%
                        ERA at Home
                    2025
                                    -52%
                        ERA at Home
                    | ERA | WHIP | IP | K/9 | BB/9 | |||||
|---|---|---|---|---|---|---|---|---|---|
| Since 2023Home | 2.33 | 0.88 | 19.1 | 8.8 | 1.9 | ||||
| Since 2023Away | 8.06 | 2.26 | 25.2 | 8.8 | 8.1 | ||||
| 2025Home | 2.57 | 0.57 | 7.0 | 5.1 | 0.0 | ||||
| 2025Away | 5.40 | 1.70 | 10.0 | 9.9 | 6.3 | ||||
| 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
2.14K/9
7.9BB/9
3.7HR/9
2.1Fastball
97.4 mphERA
4.24WHIP
1.24BABIP
.233GB/FB
0.63Left On Base
84.4%Exit Velocity
85.5 mphBarrels/BBE
4.4%Spin Rate
2232 rpmBalls Hit 95+ MPH
26.7%Swinging Strike
11.4%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
     
                  Dispatched to Triple-A
The Mariners optioned Kowar to Triple-A Tacoma on Tuesday.
                  Analysis
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                  Back in Seattle
The Mariners recalled Kowar from Triple-A Tacoma on Friday.
                  Analysis
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                  Sent back to Tacoma
The Mariners optioned Kowar to Triple-A Tacoma on Wednesday.
                  Analysis
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                  Back with M's
The Mariners recalled Kowar from Triple-A Tacoma on Thursday.
                  Analysis
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                  Heading to Triple-A
The Mariners optioned Kowar to Triple-A Tacoma on Monday, Shannon Drayer of SeattleSports.com 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."
