Why Red Sox Might Have to Call Up Tommy Kahnle for Astros Series

An explainer on the "upward mobility clause"

Detroit Tigers pitcher Tommy Kahnle walks off the field after the 3-2 loss to the Seattle Mariners in 15 innings at ALDS Game 5 at T-Mobile Park in Seattle on Friday, Oct. 10, 2025. | Junfu Han / USA TODAY NETWORK via Imagn Images

Tommy Kahnle came to the Boston Red Sox late in the offseason, and it was clear that the 11-year veteran reliever would need to build up in Triple-A.

Now that the first month of the season is coming to a close, however, the Red Sox may be forced into a decision on whether to bring him up to the big leagues. Fortunately, they would only have to do so if one of their rival clubs is willing to move mountains for him.

Kahnle has a May 1 upward mobility clause, meaning another club could sign him to its active roster if the Red Sox won't call him up to theirs. Boston would have a chance to match, but it only becomes an issue if one of those other 29 teams forces the action.

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Will Kahnle be in Boston soon?

Oct 7, 2025; Detroit, Michigan, USA; Detroit Tigers pitcher Tommy Kahnle (43) delivers a pitch in the fourth inning against the Seattle Mariners during game three of the ALDS round for the 2025 MLB playoffs at Comerica Park. Mandatory Credit: Rick Osentoski-Imagn Images | Rick Osentoski-Imagn Images

In the event that the Red Sox do feel compelled to call up Kahnle, interim manager Chad Tracy expressed confidence in the 36-year-old on Wednesday. Tracy had been managing Kahnle in Triple-A for most of the month before Boston shockingly fired Alex Cora on Saturday.

“For a veteran of his caliber that’s been around, yes, he can help out,” Tracy saidper Christopher Smith of MassLive. “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.”

Through 8 1/3 innings with Triple-A Worcester as of Thursday, Kahnle had allowed three earned runs on eight hits with eight strikeouts and three walks. If he were called up, his minor-league deal and veteran status would mean he'd need to stay on the active roster to avoid being exposed to waivers.

There's really no decision to be made yet on Kahnle's part, even if he could be in the majors as soon as Friday. On June 1, however, he has an opt-out available if he has still not yet been added to the big-league roster.

Boston has three relievers who have an option available, two of whom have already spent time in Triple-A this season in Zack Kelly and Tyler Samaniego. If they want Kahnle to stick around and are forced into action, one of those two is likely headed down.