Outfielder Jason Repko, who was promoted from Triple-A Pawtucket a week ago, sustained a slight separation of his left shoulder while banging into the wall during a great catch in Friday's 6-2 loss to the Yankees.
Repko was out of the starting lineup on Saturday.
The Red Sox are hoping to avoid putting Repko on the disabled list, particularly with Jacoby Ellsbury and Carl Crawford already sidelined.
Darnell McDonald, Ryan Sweeney and Cody Ross started Saturday's game in the outfield. Nate Spears, a utility man, can go to the outfield if needed. Mike Aviles, Boston's starting shortstop, played right field in winter ball.