Detroit Lions wide receiver Calvin Johnson (81) tries to haul in a pass but has it knocked away in the first half of an NFL football game Saturday, Dec. 24, 2011, in Detroit. (AP Photo/Duane Burleson)

FILE - In this Dec. 24, 2011, file photo, referee Ed Hochuli (85) signals during the second quarter of an NFL football game between the Detroit Lions and the San Diego Chargers in Detroit. The NFL and referees' union reached a tentative agreement on Wednesday, Sept. 26, 2012, to end a three-month lockout that triggered a wave of frustration and anger over replacement officials and threatened to disrupt the rest of the season. (AP Photo/Carlos Osorio, File)

FILE - In this Dec. 24, 2011, file photo, referee Ed Hochuli (85) signals during the second quarter of an NFL football game between the Detroit Lions and the San Diego Chargers in Detroit. The NFL and referees' union reached a tentative agreement on Wednesday, Sept. 26, 2012, to end a three-month lockout that triggered a wave of frustration and anger over replacement officials and threatened to disrupt the rest of the season. (AP Photo/Carlos Osorio, File)