Ferdinand 'Six Weeks From Return'

England captain Rio Ferdinand's knee problem may sideline him until early September, according to Manchester United manager Sir Alex Ferguson.

The 31-year-old suffered a ligament injury while training with England on 4 June, putting him out of the World Cup.

"Rio is probably around six weeks away from playing," Ferguson told the Manchester United website.

It means the defender is doubtful for England's Euro 2012 qualifiers against Bulgaria and Switzerland in September.

It was initially hoped that Ferdinand would be fit for Manchester United's opening Premier League game against Newcastle on 16 August.

However, the latest prognosis means he is likely to miss two further league games, away at Fulham on 22 August and the game against West Ham at Old Trafford on 28 August.

Ferdinand suffered his injury in a collision with team-mate Emile Heskey during England's first training session in Rustenburg as they prepared for the World Cup in South Africa.

The injury was a devastating end to what had been a disappointing season for Ferdinand, who was restricted to only 13 Premier League starts for United and 21 appearances overall because of a back injury.

He will definitely miss England's first post-World Cup friendly against Hungary on 11 August and manager Fabio Capello is unlikely to risk him against Bulgaria and Switzerland on 3 and 7 September unless he has seen competitive action for his club before then.

In more positive news for United, meanwhile, right-back Gary Neville and winger Antonio Valencia have returned to full training following a calf injuries.

However, striker Michael Owen (hamstring) has yet to resume training and midfielder Anderson is due to return in late September from the cruciate ligament injury he suffered in February.

With the rest of the squad returning to England following their pre-season tour of the United States, midfielder Owen Hargreaves has remained behind to continue treatment after a recurrence of his long-standing tendinitis problem.