...third quarter of an NFL football game against the St. Louis Rams on Sunday, Nov. 22, 2009, in St. Louis. Warner was taken out of the game after an injury in the second quarter...

Miami Dolphins' Ronnie Brown, center, is helped off the field with an ankle injury during third-quarter NFL football action against the Tampa Bay Buccaneers in Miami, Sunday, Nov. 15, 2009. (AP Photo...

Miami Dolphins' Ronnie Brown, center, is helped off the field with an ankle injury during third-quarter NFL football action against the Tampa Bay Buccaneers in Miami, Sunday, Nov. 15, 2009

WASHINGTON - OCTOBER 28: National Football League Commissioner Roger Goodell (L) testifies with others before the House Judiciary Committee about football brain injuries on Captiol Hill October 28, 2009 in Washington...

...conference at the Switzer Center. Bradford skipped last year's NFL draft to continue his collegiate career but suffered a season ending shoulder injury against Texas

...Philadelphia Eagles during an NFL football game in Charlotte, N.C., Sunday, Sept. 13, 2009. From Delhomme's 11 turnovers in two games to backup Josh Mc Cown's leg injuries, the Panthers are in...

...in drills during an NFL football training session on Sunday, Aug. 16, 2009, in Englewood, Colo. Marshall has been sidelined the past two weeks to take care of a leg injury and be at his...

...Bengals training room, Monday, Sept. 10, 2007, in Cincinnati, urges NFL football players to keep their heads up when they tackle to help prevent injuries. (AP Photo/Al Behrman

...coach Eric Mangini yelling during an NFL game against the Detroit Lions, in Detroit. Mangini says he was frustrated at losing when he suggested the Detroit Lions faked injuries in Sunday's game. During his...

...sent a wide-ranging memo about concussions to NFL teams on Tuesday, Nov. 24, 2009, saying the co-chairmen of the league's committee on brain injuries have resigned and that he is examining potential...

...sent a wide-ranging memo about concussions to NFL teams on Tuesday, Nov. 24, 2009, saying the co-chairmen of the league's committee on brain injuries have resigned and that he is examining potential...

...coach Perry Fewell talking with an assistant coach during an NFL game against the Jacksonville Jaguars, in Jacksonville, Fla. With a rising amount of injuries, Fewell doesn't have much time to regroup as the...

FILE - These are 2009 file photos showing Green Bay Packers football players Al Harris, left, and Aaron Kampman. Green Bay cornerback Al Harris and li...

...third quarter of an NFL football game against the St. Louis Rams on Sunday, Nov. 22, 2009, in St. Louis. Warner was taken out of the game after an injury in the second quarter...

...Redskins offensive tackle Chad Rinehart (75) is carted off the field following an unknown injury by emergency personnel during an NFL football game against the Dallas Cowboys, Sunday, Nov. 22, 2009 in Arlington, Texas. The...