A source told The Boston Globe that Ellsbury appears to have partially dislocated his shoulder breaking up a double play during the Sox home opener Friday and could be out as many as eight weeks.
The injury was still being examined late Friday, but the Globe's source said, "It's not good."
To fill the gap, Valentine will likely move Cody Ross into Ellsbury's center field slot, a position Ross says he is very comfortable with. The Globe said Ryan Sweeney and Darnell McDonald were also available.
The Sox were also expected to call up minor-leaguer Che-Hsuan Lin to bolster an outfield already depleted by Carl Crawford's injury. The Globe said Lin possesses an above-average throwing arm.