Montgomery departed Sunday's game at Tampa Bay due to an undisclosed injury, Tim Twentyman of the Lions' official site reports.
Montgomery seemed to be favoring his left side after he was tackled hard from behind in the second quarter. After going to the sideline, he eventually walked with team trainers to the locker room. At the time of his exit, he had six carries for 14 yards and one catch (on one target) for 19 yards. As long as Montgomery is sidelined, Craig Reynolds likely will lead the Lions backfield with rookie Jahmyr Gibbs (hamstring) sidelined.