The New York Giants lost starting cornerback Prince Amukamara for the second half of last night’s loss to the Dallas Cowboys after he suffered what was later diagnosed as a concussion, according to Dan Graziano of ESPN.com.

Amukamara sustained the head injury when he collided helmet-to-helmet with Giants safety Ryan Mundy. Following the grisly run-in, both players were eventually able to regain their feet and leave the field under their own power. Each player went straight to the locker room, as the half was coming to an end.

Following the half-time hiatus, only Mundy returned to the contest. Amukamara wasn’t cleared to resume play, as it was reported that he would miss the remainder of the game with a concussion.

Because Amukamara has been diagnosed with a concussion, he’ll have to pass the league’s tests before he’s able to return for the Giants. It’s not clear how long this will take, but over time we’ve seen players return soon and others require longer absences due to head injuries.

As a result of Amukamara’s injury, the Giants used Aaron Ross to replace him opposite fellow starter Corey Webster. New York continued using Terrell Thomas as the slot corner.