The 29-year-old received a straight red card for violent conduct after clashing with Argentina striker Carlos Tévez during QPR’s 3-2 defeat at the Etihad Stadium on Sunday.
The midfielder also lashed out at Sergio Aguero and Vincent Kompany before being escorted off the pitch by former City team-mate Micah Richards and QPR staff.
Barton is facing an automatic four-game ban for his second red card of the season, and the Football Association are expected to hand out a further punishment to the midfielder.
A club statement read: “Queens Park Rangers can confirm that a full investigation in relation to Joey Barton’s dismissal and subsequent events against Manchester City on Sunday will be carried out following the conclusion of his FA hearing.”
The FA extended the deadline by which Barton was to respond to his two charges of alleged violent conduct to 1200BST on Wednesday following a request from his representatives.
Barton could also find himself in trouble for his Tweets after Sunday’s game, with the former City midfielder questioning Mike Dean’s decision to show a red card for the incident.
“People are forgetting Tévez started the fracas by throwing a punch to the head,” Barton wrote. “Can do nothing but apologise to the players and the fans. Still don’t think its a sending off.
“The head was never gone at any stage, once I’d been sent off, one of our players suggested I should try to take one of theirs with me. It never worked but god loves a trier.”
On Monday, Barton took to his Twitter page to apologise to QPR supporters for his actions.
“Right, enough about yesterday, I apologise to everyone offended by it,” he said. “If that’s not enough for some, so be it. Life is too short.”
He added: “Things happen on the pitch, in the heat of battle sometimes. Not how we always plan them to happen.”
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