Boston placed right-hander Justin Slaten on the 60-day injured list a month ago with right elbow inflammation, and the calendar has caught up. With the regular season ending September 28, Slaten will not pitch again in 2025. The Red Sox confirmed the timeline Tuesday, closing the book on a year in which Slaten threw 28.1 innings across 31 appearances before the elbow barked in late July.
Slaten posted a 3.81 ERA and held righties to a .198 batting average, giving manager Alex Cora a reliable leverage option behind closer Kenley Jansen. His absence removes one setup arm from a bullpen that already leans on Chris Martin, John Schreiber, and Brennan Bernardino in high-leverage spots. The timing is poor: Boston sits four games out of the final Wild Card slot with 27 games remaining, and the front office is debating whether to claim arms off waivers or hand innings to Triple-A Worcester call-ups.
The bigger question is offseason. Slaten is pre-arbitration and under team control through 2028, so the Red Sox retain the asset. But elbow inflammation in a reliever triggers the standard protocol: rest, imaging, second opinion, possible platelet-rich plasma injection if the UCL shows wear. Chief Baseball Officer Craig Breslow will want clarity by November, when Boston begins mapping its 2026 bullpen budget. If Slaten needs any surgical intervention—even a minor cleanup—his spring availability becomes uncertain, and that changes whether the Red Sox go hunting for a multi-year setup arm in free agency or lean on internal depth.
Boston's bullpen ERA sits 4.12, 19th in MLB, and the club has already cycled through 14 relievers this season. Slaten's injury is not the reason the playoff push stalled, but it removes one certainty from a unit built on matchups and sequencing. The front office will now watch how Schreiber and Bernardino hold up over the final month, and whether any waiver claims before August 31 can add a serviceable arm without surrendering 40-man roster flexibility for 2026.
Slaten's next imaging is scheduled for mid-September. If the elbow is clean, he reports to spring training on time. If not, the Red Sox will need to account for his absence when they begin conversations with free-agent relievers in November. Either way, the 2025 season is over for him, and Boston's bullpen depth chart just lost one name it was counting on.