Sources: Eagles' Mike Wallace out indefinitely with ankle injury

Philadelphia Eagles wide receiver Mike Wallace, spotted in a walking boot after a loss to Tampa Bay on Sunday, suffered a potentially season-ending ankle injury in that game, sources told ESPN's Adam Schefter.

Wallace is undergoing further testing Monday to determine the specific nature of his ankle injury, but he is out indefinitely.

The injury makes the Eagles suddenly thin at wide receiver. Mack Hollins was placed on injured reserve before Week 1 with a groin injury, and Philadelphia is still waiting for Alshon Jeffery to return from shoulder surgery.

Wallace suffered his injury in the first half of the Eagles' 27-21 loss to the Buccaneers.

He was targeted three times in the Eagles' first two games but didn't have a reception.