Cubs third baseman Aramis Ramirez dislocated his left shoulder in the third inning of Friday's loss to the Brewers.
Ramirez suffered the injury while diving in an attempt to field a hit by Milwaukee's Ryan Braun.
He could miss 4-6 weeks of action, prompting Chicago to make a quick move for Ryan Freel, formerly of Baltimore.
"Seems like I can't be out there right now this year," Ramirez said, referring to calf and back injuries. "I've been hurt all the time."
Ramirez Dislocates Shoulder In Cubs' Loss