Tampa Bay Buccaneers running back Doug Martin suffered a concussion during Sunday's game against the Atlanta Falcons, the team announced. The injury is another knock for Martin, who missed the first three games of the season stemming from last year's failed drug test. Since the ban was lifted, Martin has rushed 112 times for 343 yards and two touchdowns as Tampa Bay's bell cow. He's also managed seven receptions for 60 yards.