ASHBURN, Va. � Chris Samuels says he played his entire NFL career knowing he was at risk because of a spinal condition.

The six-time Pro Bowl left tackle for the Washington Redskins formally announced his retirement Thursday. He says it�s hard to walk away from the game, but doctors have advised him he shouldn�t play again.
Samuels� upper body went limp when he banged heads with a defensive player Oct. 11 in a game against the Carolina Panthers. He said he�s had similar sensations several times during his 10-year playing career, the result of a spinal condition called stenosis.
Samuels says he�d like to become a coach. He�s accepted a minority internship to assist the Redskins coaching staff during the offseason.