Wayne Rooney ruled out of Manchester United's match against Blackburn Rovers

Sir Alex Ferguson has confirmed that Wayne Rooney will miss Manchester United's match against Blackburn Rovers on Sunday after the striker aggravated an injury to his right ankle against Bayern Munich.

The England striker was a surprise inclusion in the United side that went out of the Champions League at Old Trafford on Wednesday night. Rooney lasted only 55 minutes of the quarter-final second leg, after going over on the same ankle and suffering a burst blood vessel just below the joint.

Ferguson insists the United still have "a great chance" of retaining the Premier League title, even though he concedes the advantage lies with Chelsea. "Five wins would give us a great chance," Ferguson said. "Chelsea will be thinking five wins gets them the title and, at a crucial time of the season, the advantage is with them.

"But we hope that something can happen. You would rather be in Chelsea's position but we have a chance of winning the league, and so have Arsenal, who are a point behind us."

The absence of Rooney seemed likely the moment he limped out of the Bayern game following the second-half dismissal of full-back Rafael. Yet Ferguson insists the problem is not long-term and should have his 34-goal forward fit for next weekend's Manchester derby at Eastlands.

"We won't have Wayne for Sunday," Ferguson added. "It is nothing serious, as we said the first time he got the injury. I think he will be ready for the Manchester City game because we have more time to work on it."

Ferguson is expected to make further changes given the energy United expended on Wednesday, with Paul Scholes, Gary Neville and Ryan Giggs all set to be included, along with John O'Shea, who was introduced as a substitute in midweek, his first appearance since November.