Brown suffered the injury in the fourth quarter after rushing for 64 yards on 13 carries.
The second-year back from North Carolina State had emerged as the team's No. 2 back behind Ahmad Bradshaw, rushing for 385 yards and eight touchdowns on the season. The Giants will now have to depend more on rookie first-round pick David Wilson.
Brown's wasn't the only significant injury for the Giants.
Safety Kenny Phillips, playing in his first game in nearly two months Sunday after missing six games with a right knee injury, suffered an injury to the same knee during the third quarter.