PFA chief Gordon Taylor has hit out at QPR captain Joey Barton.

Barton's future at QPR is in doubt after he elbowed Carlos Tevez, kicked Sergio Aguero and appeared to headbutt Vincent Kompany during Rangers' 3-2 defeat at Manchester City on Sunday.

He invited more controversy by slamming Alan Shearer and Gary Lineker on Twitter.

"If you come out with stuff like that you are going to deserve to be heavily sanctioned," the chief executive of the Professional Footballers' Association said.

"He is his own worst enemy when he says stuff like that and he has been upsetting a lot of people in the game with good reputations.

"We try to deal with Joey Barton and it is not getting any easier.

"I just feel sometimes like it is pushing a boulder up a hill, it slips back and you decide whether to go again.

"It has certainly been a backward step for him and his future in the game.

"There are people that seem to be improving and then slip back, it is a human condition. No one is perfect but you only have one career."