New York Jets Rex Ryan throws a challenge flag against the Kansas City Chiefs, Dec. 11, 2011, in East Rutherford, N.J. (AP Photo/Bill Kostroun)

Pittsburgh Steelers head coach Mike Tomlin throws a challenge flag in an NFL wild card playoff football game against the Denver Broncos, Jan. 8, 2012, in Denver. The Broncos won 29-23 in overtime. (AP Photo/Chris Schneider)

Houston Texans Gary Kubiak watches a replay before challenging a call against the Tennessee Titans, Sept. 30, 2012, in Houston. (AP Photo/Dave Einsel)

Green Bay Packers Mike McCarthy throws the challenge flag against the New Orleans Saints, Sept. 30, 2012 in Green Bay, Wis. (AP Photo/Jeffrey Phelps)

New Orleans Saints Sean Payton holds the challenge flag in the fourth quarter of a game against the Tennessee Titans, Dec. 11, 2011, in Nashville, Tenn. (AP Photo/Frederick Breedon)

New York Giants head coach Tom Coughlin throws the challenge flag during a NFL divisional playoff football game against the Green Bay Packers, Jan. 15, 2012, in Green Bay, Wis. (AP Photo/Jeffrey Phelps)

Head coach John Fox of the Denver Broncos speaks to officials while holding a challenge flag during a game against the Atlanta Falcons, Sept. 17, 2012, in Atlanta. (AP Photo/Pouya Dianat)

Philadelphia Eagles coach Andy Reid considers challenging a play against the Cleveland Browns, Aug. 24, 2012, in Cleveland. Reid could not get the attention of the officials and put the flag back in his pocket. (AP Photo/Mark Duncan)

Baltimore Ravens head coach John Harbaugh picks up his red flag after challenging a play against the Philadelphia Eagles, Sept. 16, 2012, in Philadelphia. (AP Photo/Mel Evans)

New England Patriots head coach Bill Belichick tosses the challenge flag against the Dallas Cowboys in Foxborough, Mass., Oct. 16, 2011. It was eventually ruled a touchdown by Patriots wide receiver Wes Welker. (AP Photo/Elise Amendola)

Detroit head coach Jim Schwartz throws a red challenge flag after a fight between Lions and Chicago Bears players in Chicago, Nov. 13, 2011. (AP Photo/Nam Y. Huh)

Rams head coach Jeff Fisher throws the red flag during a game between St. Louis and the Washington Redskins, Sept. 16, 2012, in St. Louis. (AP Photo/Tom Gannam)