The Marlins transferred Kempner (elbow) to the 60-day injured list Friday.
The transaction clears space on the 40-man roster for the addition of Logan Driscoll. Kempner recently underwent UCL surgery on his right elbow and will be sidelined, at minimum, until late in the 2027 season.
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Marlins' William Kempner: Surgery on tap
Rotowire
Marlins manager Clayton McCullough said Wednesday that Kempner will require surgery for his sprained right elbow, Jordan McPherson of the Miami Herald reports.
The Marlins aren't expected to provide further details until the operation is performed, but Kempner will presumably require Tommy John or internal brace surgery (or a hybrid of the two), which will keep him out for the rest of the 2026 season and most, if not all, of the 2027 campaign. The 25-year-old righty was placed on the injured list July 12 and had initially taken the rest-and-rehab approach for his treatment plan, but he apparently wasn't progressing as well as the Marlins had hoped. He'll close the season with a 2.92 ERA, 0.97 WHIP and 14:4 K:BB in 12.1 innings over nine appearances with the big club.
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Marlins' William Kempner: Recalled from Triple-A
Rotowire
The Marlins recalled Kempner from Triple-A Jacksonville on Friday, Christina De Nicola of MLB.com reports.
Kempner was sent down last month despite logging nine scoreless innings with a 10:2 K:BB in six relief appearances. The 25-year-old will likely fill a middle relief role, but his stay in the majors could be brief as the Marlins will need a spot next week for a fifth starter, expected to be Janson Junk (shin).
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Marlins' William Kempner: Returns to Triple-A
Rotowire
Kempner was optioned to Triple-A Jacksonville on Tuesday.
The right-hander fired 2.1 scoreless innings Monday against the Phillies and is being sent down Tuesday in favor of a fresh bullpen arm (Dax Fulton). Kempner has given up just three hits with a 10:2 K:BB across nine scoreless frames in the majors this season, so it should only be a matter of time before he gets another look with the big club.
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Marlins' William Kempner: Recalled from Triple-A
Rotowire
The Marlins recalled Kempner from Triple-A Jacksonville on Tuesday, Christina De Nicola of MLB.com reports.
He's grabbing the roster spot vacated by Chris Paddack, who was designated for assignment. Kempner holds a 6.46 ERA this season with Jacksonville but has struck out a whopping 34 batters over 15.1 innings. He will be making his major-league debut when/if he enters a game.
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Marlins' William Kempner: Sent to Triple-A
Rotowire
The Marlins optioned Kempner to Triple-A Jacksonville on Sunday.
Kempner was added to Miami's 40-man roster in November but was never a likely bet to crack the Opening Day roster. The 24-year-old had a quality showing in his first taste of Triple-A last year with a 2.65 ERA, 1.35 WHIP and 25:15 K:BB over 17 innings, and he could make his MLB debut at some point in 2026 if he continues to pitch well for Jacksonville.
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Marlins' William Kempner: Joins 40-man roster
Rotowire
The Marlins selected Kempner's contract from Triple-A Jacksonville on Tuesday.
Kempner was acquired from the Giants last winter in exchange for international bonus pool space, and the Marlins won't leave him exposed to potentially being selected during the upcoming Rule 5 Draft. Across three minor-league levels in 2025, the 24-year-old pitched to a 2.26 ERA, 1.15 WHIP and 95:40 K:BB over 67.2 innings.
