Updated

Tampa, FL (SportsNetwork.com) - Tampa Bay Buccaneers running back Doug Martin has been diagnosed with a labrum tear in his left shoulder, an injury that could sideline the second-year pro for the remainder of the season.

Head coach Greg Schiano told reporters on Monday that Martin is highly unlikely to play when the Buccaneers host Carolina this coming Thursday, but added that the team has not ruled out the possibility of him returning at some point in the season.

"[We've] just got to wait and see," said Schiano. "If it was season-ending, I'd let you know, but I don't feel that it is right now. We don't feel that it is, our medical team. We're just going to play it by ear and go from there."

Martin sustained the injury during the third quarter of Sunday's 31-23 loss at Atlanta. The Buccaneers cannot place him on injured reserve as a designated to return player, having already used that allotted option on cornerback Danny Gorrer.

Rookie Mike James replaced Martin in Sunday's loss and is expected to take over as Tampa Bay's lead back, with veteran Brian Leonard remaining in the third-down role.

Martin put together an outstanding rookie campaign in 2012, compiling 1,454 rushing yards and 11 touchdowns while gaining an additional 472 yards on 49 catches. The 24-year-old has rushed for 456 yards on 127 attempts so far this season, though his 3.6 yards-per-carry average is considerably lower than last year's.