Acknowledging what had become inevitable, the Red Sox announced Monday that outfielder Carl Crawford will undergo Tommy John surgery on his left elbow Thursday, finishing his 2012 season and placing the start of his 2013 season very much in doubt.

Crawford suffered the elbow injury in spring training as he attempted to return from surgery on his wrist, which had been performed in January.

He missed the first 3 1/2 months this year and returned just after the All-Star break. Crawford played in 31 games, with a slash line of .282/.306/.479 with three homers, 19 RBI and five stolen bases.