CLEVELAND, Dec. 3 (UPI) -- Cleveland running back Jamal Lewis has been placed on injured reserve following a concussion suffered in last Sunday's 16-7 loss to Cincinnati.
The team said on its Web site Lewis, 31, suffers from post-concussion syndrome, which brings an early end to his 10-year career.
A Cleveland Plain Dealer report said he met with a brain trauma specialist Wednesday.
The former Tennessee product, a first-round pick by Baltimore in the 2000 NFL Draft, had said the 2009 season would be his last.
He is 21st on the NFL's all-time rushing list with 10,607yards, 500 in nine games this season.
Cleveland safety Brodney Pool (IR) adds to the growing list of players with recent concussions, including running backs Brian Westbrook of Philadelphia and Clinton Portis of Washington, Philadelphia wide receiver DeSean Jackson and quarterbacks Ben Roethlisberger of Pittsburgh and Kurt Warner of Arizona.
Commissioner Roger Goodell has issued stricter guidelines on when a player should be allowed to return to play.