Washington Redskins tight end Jordan Reed, who has suffered multiple concussions during his career and already has been ruled out of Monday night's game against the Chicago Bears because of his latest one, might not be able to return at all, league sources told ESPN.

There are those within the Redskins organization and around the league who are concerned Reed will not be able to play again, according to sources. Reed will continue to undergo testing, but the player, the team and doctors know what he is up against.

Any player who has suffered the number of concussions that Reed has -- it is difficult to pinpoint the exact number -- puts himself at grave risk by playing again.

The Redskins had been counting on having Reed, a former Pro Bowler and one of their best players, this season. But in Washington's third preseason game last month against the Falcons, Reed suffered his latest concussion, which already has knocked him out of the first three games of the season.

Reed, 29, still would like to resume playing, but it is hardly automatic that he will. The more time that goes on without him coming back, the less likely it is that he will return to a sport in which he has excelled.