A scan on Wayne Rooney’s right ankle revealed yesterday that he has sprained it — keeping him out of football for four to six weeks and is likely to mean he will play only two more league games for Manchester United this season.

The results of the scan undertaken at a medical centre in Whalley Range in Manchester yesterday are by no means as bad as they could have been. There are no torn ligaments in the ankle, which bears out the assurances Fabio Capello was given early yesterday that the striker would be available for the World Cup. Rooney is more likely to miss four weeks, six weeks out being at the extremity of expectations, though that would still see him miss seven United games and be back in the side for the visit to Sunderland on May 1.

It also means that Rooney has precious little time before England’s countdown to the World Cup begins in earnest, with internationals at home to Mexico on May 24 and against Japan in Austria six days later.

United will be deprived of Rooney for a critical, challenging period of the season, starting with Saturday’s Premier League summit meeting with Chelsea at Old Trafford. They then have the second leg with Bayern, followed, after a tricky match at Blackburn, by the Manchester derby at Eastlands on April 17. Both legs of any putative Champions League semi-final, against Lyon or Bordeaux, are unlikely, as well as Tottenham’s visit to Old Trafford. United’s title bid may rest with Dimitar Berbatov’s ability to demonstrate he was worth the £30.5m Sir Alex Ferguson paid for him the summer before last.

Though Rooney left the field in some distress in Munich, he did not wear the demeanour of an individual whose season was over, leaning over the back of his seat to speak to the players behind him during a flight and the in-flight film, Mr Bean, may have lifted his spirits on the two-hour journey back into Manchester Airport, which concluded with a particularly bumpy landing in a grey North-west.

Rooney did seem to go over on his ankle rather than twist it — twisting being the action which tends to damage ligaments — and his manager had suggested immediately that the injury may not be too bad.

The striker did not come through the usual airport departure channel at Munich but was instead driven straight to the plane in a people carrier, on crutches as he boarded. An Audi was awaiting him at Manchester in which, after he waited on the plane while other passengers disembarked, he was whisked through a VIP exit avoiding passport control.

A source close to the United dressing room suggested that the initial prognosis was two to three weeks out, though this had been extended to a possible four weeks before the scan was carried out.

Capello, who looked on with horror from the stands at the Allianz Arena when Rooney crumpled to the turf in added time, would have taken news of a four-week lay-off on Wednesday night, though that means his prime asset may have only two more domestic matches this season — the visit to Sunderland and final league fixture at home to Stoke City — as well as the Champions League final if United make it there. But that would at least give him time to rest the knee injury which has plagued him in recent weeks — his kneecap tendons have been strained.

Capello travelled back earlier from Munich. “I am waiting to hear about the scan, and I will try and speak with Wayne. When he went down I was not happy. It is not good for me for any England player to suffer an injury,” he said

“It would be a massive blow for us if Wayne doesn’t play [in the games coming up],” said Darren Fletcher.

“He is quite obviously one of the best players in the world. But we have other good players. If Wayne isn’t available, we will rally round. Berbatov, Valencia and Giggs came off the bench against Bayern so we still have a lot of quality.”

Meanwhile, Wayne Rooney should easily be fit for the World Cup if his injury is just ankle ligament damage but he could miss the rest of Manchester United's season, according one of the UK's leading orthopaedic surgeons.

He had a scan on the ankle to determine the extent of the damage but Simon Moyes, who specialises in sports injuries, says it is more than likely that he will have recovered in six weeks time.

Moyes, who works out of the Wellington Hospital in London, said: “He will need an MRI scan to confirm the diagnosis but more importantly to exclude any other injury in or around the ankle joint such as cartilage damage or a minor fracture.

“Assuming Wayne Rooney has a pure lateral ligament injury there is a 90-95% chance of him being satisfactorily recovered at six weeks with an accelerated physiotherapy/rehabilitation programme.

“This should easily allow him to be fit enough for England's first match on June 18.”