GLENDALE, Ariz. -- An MRI of Erik Bedard on Monday showed the left-hander suffered a strain of the teres major muscle in the back of his shoulder, the team announced.
"I think we kind of expected that," manager Don Mattingly said. "We've been through it with Kersh, with Paco and with Brandon last year."
Bedard, 36, left his start on Friday against the Rangers in San Antonio after just one inning, feeling something in his side.
There is no timetable yet for Bedard's return, but both Clayton Kershaw and Paco Rodriguez suffered teres major muscle strains in 2014 for the Dodgers, and both missed six weeks. Brandon League had a lat strain during spring training last year and missed three weeks.
Bedard allowed three runs on five hits in five innings in Cactus League play, with three walks and three strikeouts in his three games, including two starts. He was 4-6 with a 4.76 ERA and 4.39 FIP in 17 games, including 15 starts with the Rays in 2014.
The Dodgers signed Bedard to minor league contract on January 15 with a non-roster invitation to big league camp. He has a pair of opt-out dates in his minor league deal that can allow him to become a free agent, one if he isn't added to the major league active roster by May 1, and another on June 15.