Willingham is expected to go out on a rehab assignment once he's cleared to play, as he hasn't played in a game for more than a month.
Willingham, 35, was hitting .294/.435/.353 with a double and an RBI in six games before the injury.
Rhett Bollinger is a reporter for MLB.com. Read his blog, Bollinger Beat, and follow him on Twitter @RhettBollinger. This story was not subject to the approval of Major League Baseball or its clubs.