Chicago Bears running back David Montgomery is expected to be sidelined two-to-four weeks due to a groin injury, a source told NFL Network's Ian Rapoport.
Montgomery suffered the injury during an individual drill at practice Wednesday, though he avoided what was initially thought to be a knee issue.
The ball carrier's reported timetable leaves open the possibility of him suiting up for the Bears' season opener against the Detroit Lions on Sept. 13.
The 23-year-old was Chicago's leading rusher as a third-round rookie last season, racking up 889 yards and six touchdowns on 242 rushing attempts. He also recorded 25 receptions for 185 yards and one score.