The move, which the Redskins announced was made because of "conduct detrimental to the club," comes after a long, difficult back-and-forth between Haynesworth, a two-time All-Pro with a $100 million contract, and first-year Washington head coach Mike Shanahan, who won two Super Bowls with the Denver Broncos.
Haynesworth skipped offseason workouts, boycotted a mandatory minicamp, needed 10 days to pass a conditioning test at training camp, did all he could to resist a change in the defensive scheme and then eventually became a part-time player.
His main gripe has been that he shouldn't be playing nose tackle in a 3-4 defense.
The Redskins said general manager Bruce Allen told Haynesworth about the suspension Tuesday. Haynesworth was inactive for Washington's 31-7 loss at the New York Giants on Sunday, which dropped the Redskins to 5-7.
In the team's statement Tuesday, Shanahan is quoted as saying that Haynesworth "repeatedly refused to cooperate with our coaching staff in a variety of ways over an extended period of time."
Shanahan also said Haynesworth "consistently indicated" to defensive coaches that he wouldn't play in certain defensive packages and refused to follow coaches' instructions in practice and during games.