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Veteran reliever Tommy Kahnle, pictured during his New York Yankees tenure, faces a final Friday roster decision from the Boston Red Sox.

The Boston Red Sox must decide by Friday whether to promote veteran right-hander Tommy Kahnle or risk losing the former New York Yankees setup man to a rival bullpen, with his contract clause activating May 1, according to a report by MassLive.

The timing is inconvenient, to say the least. Boston’s rotation took another blow this week with lefty ace Garrett Crochet landing on the injured list, and the club’s bullpen decisions now carry added weight heading into a weekend series at Fenway Park against the Houston Astros.

Kahnle’s Upward Mobility Clause Forces Red Sox Decision

Kahnle, 36, signed a minor league deal with the Red Sox in March and has been pitching out of the Triple-A Worcester bullpen since. His contract contains an upward mobility clause set to trigger Friday, May 1, according to MassLive reporter Christopher Smith. Once triggered, all 29 other clubs gain the right to sign Kahnle directly to their active rosters. If any team moves on him, Boston must either place him on its own 40-man roster or let him walk.

Kahnle, who was drafted by the New York Yankees in the fifth round back in 2010, has done everything he has needed to do in Worcester. Through 8⅓ relief innings, he owns a 3.24 ERA, a 1.32 WHIP, and has posted three consecutive scoreless outings, according to MLB Trade Rumors writer Steve Adams. He has struck out eight of 36 batters faced, allowed no home runs, and is averaging 92.7 mph on his four-seamer, a pitch he committed to throwing more frequently this season after largely abandoning it last season, his only year with Detroit.

“Last year I really liked my fastball. I just didn’t throw it, at all,” Kahnle said, as quoted by MassLive. “I don’t know if it was pitch clock, the catcher, me. There were lots of variables.”

His changeup remains the primary weapon. Opponents hit just .157 against it in 2024. From 2016 through 2024, across stints with the Chicago White Sox, New York Yankees and Los Angeles Dodgers, Kahnle posted a 3.11 ERA with a 31.1 percent strikeout rate in 271⅔ innings, per MLB Trade Rumors.

Red Sox Bullpen Picture Complicates Kahnle Decision

Interim manager Chad Tracy, who managed Kahnle in Worcester before the Red Sox fired Alex Cora last weekend and named Tracy to replace him, left no doubt about his confidence in the veteran.

“For a veteran of his caliber that’s been around, yes, he can help out,” Tracy said, according to Sports Illustrated writer Jackson Roberts. “He’s been around the big leagues for a really long time. He knows how to pitch. He’s been here, he’s pitched in the playoffs. So absolutely can help out.”

The roster math is tough, however. Boston’s bullpen ranks eighth in MLB with a 3.67 ERA and has been a rare area of strength on a team that has drastically underperformed. Only three current relievers can be optioned without waiver exposure: Zack Kelly, Tyler Samaniego, and Greg Weissert. Adding Kahnle would place a sixth non-optionable arm in the bullpen.

The cleaner solution, according to BoSox Injection reporter Brandon Glick, involves Rule 5 pick Ryan Watson, who carries a 6.62 ERA across 13 appearances. Releasing Watson would return him to the Athletics, freeing the spot Kahnle would fill. Chief baseball officer Craig Breslow is set to make the decision before the clock runs out on Friday.

If no team triggers the clause and Boston stands pat, Kahnle holds a second safety valve. He can opt out of his deal on June 1 if the Red Sox still have not called him up to Fenway.