Ludwick dislocated his right shoulder while sliding into third base in Cincinnati's opening 3-1, 13-inning loss to the Los Angeles Angels on Monday. He had surgery on Wednesday to repair torn cartilage.
Manager Dusty Baker said Ludwick is expected to be sidelined for 13 to 14 weeks.
The Reds called up Derrick Robinson to take his roster spot. The 25-year-old outfielder will make his major league debut.
Chris Heisey, who has been a reserve most of his career, will get a chance to play left field while Ludwick recovers. He started 80 games last year at all three outfield spots.