San Francisco Giants ace Madison Bumgarner, who earlier this month injured his left throwing shoulder in a dirt-biking accident, started rehab for the injury and is expected to be out until after the July 10-13 All-Star break, the team said Friday.

The 27-year-old suffered a Grade 2 AC joint sprain in the April 20 crash on the team's day off in Colorado.

Bumgarner started rehab Friday focused on improving his range of motion, Giants manager Bruce Bochy said.

Bumgarner, who's in the last year of a five-year $35 million contract extension he signed in 2012, is 0-3 with a 3.00 ERA in four starts this season.