**Manchester United are unsure how long Rio Ferdinand will be out for after the centre-back suffered a thigh injury while training on Friday.**Ferdinand, 30, faces a scan on Monday to discover the extent of the injury.
In his absence, John O’Shea captained United as they began the defence of their Premier League title on Sunday at home to Birmingham.
Ferdinand had shaken off the back injury he picked up during England’s midweek 2-2 friendly draw with Holland.