# Boston Red Sox player injury developments

> Live situation record from CLSTR: https://clstr.news/situations/boston-red-sox-player-injury-developments
> Updated: 2026-09-29T22:37:54.000Z. Sources: 7. Developments: 3.

The Boston Red Sox have faced significant roster challenges due to player injuries during the latter part of the 2026 season.

Reliever Justin Slaten was ruled out for the remainder of the season following a diagnosis of degenerative changes in his flexor mass. His treatment plan involves a platelet-rich plasma injection.

Mickey Gasper sustained a significant right biceps injury during the fifth inning of Game 1 of a doubleheader against the Chicago Cubs. Manager Chad Tracy initially indicated the injury would “probably gonna take him out,” potentially sidelining Gasper for the upcoming Wild Card Series against the New York Yankees.

Subsequent medical evaluations confirmed that Gasper suffered a full-thickness tear, occurring when a two-strike swing caused the tendon to separate entirely from the bone. Gasper has been placed on the 10-day injured list, retroactive to September 26, and has been excluded from the Red Sox playoff roster. He is scheduled to undergo surgery to repair the tear, with an expected recovery period of six to eight weeks.

## Timeline

### 2026-09-29: Mickey Gasper to undergo surgery after tearing right biceps

Boston Red Sox utility player Mickey Gasper will undergo surgery for a torn right biceps, ending his season and removing him from the team's playoff roster.

2 sources. https://clstr.news/cluster/mickey-gasper-to-undergo-surgery-after-tearing-right-biceps

### 2026-09-26: Mickey Gasper faces significant biceps injury, potentially missing Red Sox playoffs

Boston Red Sox player Mickey Gasper faces a significant biceps injury that could sideline him for the rest of the season and the upcoming MLB playoffs.

5 sources. https://clstr.news/cluster/mickey-gasper-faces-significant-biceps-injury-potentially-missing-red-sox-playoffs

### 2026-09-15: Justin Slaten ruled out for remainder of season by Red Sox

Boston Red Sox reliever Justin Slaten is likely finished for the season after degenerative changes were found in his flexor mass, requiring a platelet-rich plasma injection.

4 sources. https://clstr.news/cluster/justin-slaten-ruled-out-for-remainder-of-season-by-red-sox

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Cite as: Boston Red Sox player injury developments. CLSTR, https://clstr.news/situations/boston-red-sox-player-injury-developments