Queens Park Rangers have announced that Joey Barton's 12-match ban will stand after deciding against an appeal.
The controversial midfielder was hit with the lengthy sanction after the Football Association found the 29-year-old guilty of violent conduct on two occasions when he was sent off during QPR's 3-2 defeat to Manchester City.
The West London outfit have also confirmed that they have begun an internal investigation, which has sparked rumours that the former Newcastle United playmaker could be shown the door at Loftus Road.
A statement from the Premier League club said: "The QPR midfielder will not appeal against the independent Regulatory Commission's decision made on Wednesday and he and his team are now working in full cooperation with the club to assist in the internal investigation.
"During this period, no-one from the club or Joey Barton himself will make any further comment."
The investigation is expected to last two weeks.