Ian Rapoport of NFL Media reports that Maddox is set to have surgery to repair the injury this week after an MRI and additional medical opinions showed that it was the best course of action. Maddox is out indefinitely and could miss the rest of the season as a result of the injury.
Maddox opened the year as the Eagles' top slot corner and had eight tackles and a forced fumble before his injury. Mario Goodrich replaced him against the Vikings with Josh Jobe playing in place of James Bradberry, who missed Week Two with a concussion.
The Eagles were also without safety Reed Blankenship last week, so they may need to bring in some new bodies to ensure that they're well-stocked for next Monday's game against the Buccaneers.