Manchester United boss Sir Alex Ferguson has defended his decision to send Rio Ferdinand for an exploratory knee operation.

The defender admitted he was disappointed at having to miss two England internationals, although he accepted that it had been playing him up for a while.

‘It’s been niggling away for a while and something had to be done,’ said Ferdinand

Speaking to the Evening Standard, Ferguson stated: “The knee has been bothering Rio for some time and it was decided to perform the operation now and have the thing cleared up.”

However, it is not so much the surgery as the timing of it which has attracted attention and the lateness with which United confirmed his absence from the England squad. National coach Sven Goran Eriksson was led to believe that Ferdinand was available for selection when he prepared to announce his squad, until belatedly informed that Ferdinand was to undergo the surgery.

Meanwhile, West Ham’s Trevor Sinclair is another player to withdraw from the squad after sustaining an injury in West Ham’s Premiership encounter with Birmingham on Saturday. Blackburn’s David Thomppson is rewarded for his a sparkling form since moving to Ewood Park earlier in the season, with his first international call-up.