The Manchester United manager already faces the prospect of being without his controversial captain after his red card against Sunderland on Saturday.

Keane could also cop a Football Association ban if the governing body brings a disrepute charge against the player over comments made in his controversial autobiography.

But Ferguson will leave a decision on whether Keane should undergo an operation to the player himself.

"He has felt his hip for a while," Ferguson told the Sunday People. "The problem is what to do about it.

"He could go on for the rest of the season if he has the odd injection and treatment.

"It's possible he could stagger on until the end of the season by regathering himself as only he can do but we are actually taking it game to game at the moment.

"It will always be the player's decision but when you look at Freddie Ljungberg and Robbie Fowler you are talking two to three months out."

Ferguson jumped to the defence of Keane on Saturday after the Irishman was sent off for the 10th time in his United career.

Referee Uriah Rennie showed the red card to Keane for elbowing Sunderland's Jason McAteer in the dying seconds of their 1-1 draw at the Stadium of Light.

The former Republic of Ireland team-mates had been involved in an altercation earlier in the game from which McAteer was lucky to escape without a booking.

After the match United boss Ferguson said that the offence was "soft".

Ferguson said: "I do not think he swung an elbow - he put an arm across his face.

"If the referee deems it a sending-off I do not know what we can do. The player (McAteer) went down quickly which is disappointing."

Gordon Taylor, chief executive of the Professional Footballers' Association said he was keen to see peace break out between PFA members.

"I don't want difficult situations like Denis Wise and Callum Davidson, Keane and McAteer and Keane and Alfie Haaland," he said.

"I said at the time that it was a bad time to publish a book, it was not the best time to re-open old wounds.

"The Irish problem now looks to be impinging on the domestic game. Is this going to happen every time Roy comes up against one of his Irish colleagues?"