Giants CB Amukamara out with concussion

Giants cornerback Prince Amukamara has been knocked out of Sunday night's opener because of a concussion sustained after a helmet-on-helmet collision with a teammate.

The collision with safety Ryan Mundy occurred when they were making a tackle on Cowboys rookie receiver Terrance Williams late in the first half.

Both Amukamara and Mundy came off the field and were taken to the locker room. Mundy was cleared to return to the game after halftime.

On an earlier pass intended for Williams, the ball instead deflected off Amukamara into the arms of Mundy, who raced 91 yards before being caught from behind at the 1.