In a photo taken on Sunday, Dec. 22, 2013, Detroit Lions tight end Dorin Dickerson goes up against New York Giants free safety Ryan Mundy (21) during an NFL football game in Detroit. The Lions have placed Dickerson on injured reserve, four days after he didn't immediately tell the team's medical staff he had a concussion during a game against the Giants. Dickerson told reporters Sunday he was unconscious after a kickoff return during the 23-20 overtime loss to the Giants. Dickerson said he should've reported the concussion, but thought he could play through it. (AP Photo/Rick Osentoski)