Gallman took a big hit at the completion of an 11-yard run. He finished the game with two carries for 14 yards.
The loss of Gallman left the Giants with only undrafted rookie Jon Hilliman and fullback Elijhaa Penny at running back.
Hilliman carried the ball 10 times for 33 yards and had a fumble in his NFL debut last week against the Washington Redskins. Penny has five carries for 15 yards on the season.