Oakland Athletics right-hander Justin Sterner has been ruled out for the remainder of the season after undergoing right knee surgery in Los Angeles on Thursday. The 29-year-old reliever returned to Sacramento on Friday to commence his rehabilitation program. Sterner has been on the sidelines since July 17.

During his time on the mound this season, Sterner posted a 2-3 record with a 6.12 ERA across 42 2/3 innings pitched. The arthroscopic procedure, which focused on the interior of the knee, was performed by Dr. Mike Banffy at Cedars-Sinai Orthopedic Center. As part of the treatment, Sterner also received a platelet-rich plasma injection.

The surgery marks a premature end to Sterner's season, impacting the Athletics' bullpen depth. His return to the mound is not expected until next season, pending a full recovery from the knee procedure and subsequent rehabilitation.