Clay Matthews Injured: Packers LB Out Against Lions

Clay Matthews, the Green Bay Packers linebacker, was injured in the second half against the Lions on Sunday.

Green Bay Packers outside linebacker Clay Matthews, left, reaches for St. Louis Rams quarterback Sam Bradford during the second quarter of an NFL football game on Saturday, Aug. 17, 2013, in St. Louis. AP Photo/Seth Perlman

Clay Matthews, the Green Bay Packers linebacker, was injured in the second half against the Lions on Sunday.

Matthews was seen with his helmet off walking to the locker room in the fourth quarter.

It is unclear what the injury was.

Also unclear is if Matthews will return.