Brent Rooker – the Athletics’ designated hitter and outfielder – underwent season‑ending left knee surgery Friday, a hard blow to a leader on and off the field. Dr. Tim Mc Adams and Dr. Mike Freehill performed a debridement of Rooker's articular cartilage tear at Stanford Orthopedic Hospital in Redwood City, also removing loose bodies. Rooker, who played all 162 games last season, had been injury‑plagued, receiving a cortisone shot last month and rehabilitating from a bone bruise before seeking further evaluation. He also missed 15 games in April with a strained right oblique muscle.

A two‑time All‑Star, he batted .200 with 10 home runs and 48 games this season. Rooker received a five‑year contract worth $60 million ahead of last season. The team expects him to return by the start of spring training next year, but the knee injury will likely affect his performance in the coming campaigns.