The depth of the Green Bay Packers defense is already being tested in Week 1. Linebacker Quay Walker, cornerback Keisean Nixon and linebacker Krys Barnes all exited Sunday’s game with injuries in the second half.

Walker and Nixon both have shoulder injuries and are questionable to return, while Barnes suffered a significant lower-leg injury that required an air cast to stabilize.

The Packers identified Barnes’ injury as an ankle, and he’s already been ruled out.

Walker, the Packers’ first-round pick, made eight tackles in his regular season debut.

Nixon was injured making a third-down tackle and appeared to be in significant pain. A cart was needed to get Barnes off the field in the fourth quarter.

The Packers only have four active cornerbacks on Sunday, so there’s no backup behind Jaire Alexander, Rasul Douglas and Eric Stokes the rest of the way if Nixon can’t return.

At linebacker, Isaiah McDuffie would be the next man up behind Walker and Barnes.

Starting left guard Jon Runyan Jr. is out for the rest of the game after suffering a concussion.