Rooney has missed two games, including the victory over Barcelona, after suffering a recurrence of a hip injury in the defeat at Chelsea last month.

Ferguson feels his star striker will be limited to a substitutes' role at best when United head to the JJB Stadium, requiring a victory to retain the Premier League title.

But even if Rooney does not make it, the Scot maintains the England man will face Chelsea at the Luzhniki Stadium in Moscow in the first all-English Champions League decider.

"I am not so sure about Wayne," said Ferguson.

"Maybe I will have him as a substitute on Sunday. But he will certainly be fit for the Champions League final."

Ferguson delivered better news on the fitness of Nemanja Vidic, who suffered concussion at Stamford Bridge, as well as a nasty cut to his lip.

The tough-tackling Serbian defender has been cleared by the United medics to face Steve Bruce's men, with Ferguson confirming Vidic will play providing he comes through the remaining training sessions unscathed.

"We are very hopeful of Nemanja being fit," said the Scot.

"He is clear medically, so the next two training sessions will be very important.

"But he is much better and hopefully I can get him right for Sunday."