Barton was shown a straight red card for a wild tackle on Xabi Alonso during Newcastle's 3-0 defeat by Liverpool on Sunday.
Stand-in manager Alan Shearer condemned the challenge, saying Barton had let down himself and the club. Local media reported that Shearer had rowed with the player in the dressing-room after the match and fined him two weeks' wages.
With three games remaining, and Newcastle three points adrift of safety, Barton will incur an automatic three-game suspension from the FA anyway for his red card, prematurely ending another controversial and injury-hit season.
"Newcastle United can confirm that Joey Barton has been suspended from the club until further notice," the club said in a statement on their website.
"The club will be making no further comment on the matter at this time." Barton, who joined Newcastle for 5.8 million pounds from Manchester City two years ago, was making his first appearance since January after recovering from a foot injury.
"I thought he could do something different," Shearer said after the game. "But I didn't think he'd go on and get a red card. I'd asked him not to do that."
Barton, 26, still has a suspended six-game ban hanging over his head following his training-ground assault on former City team mate Ousmane Dabo in 2007.
Last year he was jailed for 77 days after an assault in Liverpool city centre in December 2007
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