The Oakland Athletics shut down right-hander Henderson Alvarez on Sunday, one day after he left a rehab start early with shoulder discomfort.
Alvarez, who left his start for Nashville on Saturday in the fourth inning, is now expected to make a visit to Dr. James Andrews.
The 26-year-old Alvarez underwent season-ending shoulder surgery last July and hasn't pitched in the major leagues this season. He signed a one-year contract with the A's in December after he wasn't offered a contract by the Marlins for the 2016 season.
A National League All-Star in 2014 when he was 12-7 with a career-best 2.