Sir Alex Ferguson's hopes of pulling off a second stunning treble have been hit by a massive blow, with the news that Rio Ferdinand could miss the rest of the season with his ongoing calf problems. The centre-back has been struggling with various injuries over the past couple of seasons, and has been sidelined with this calf injury since the defeat to Wolves in early February.

Rio's continued fitness troubles have resulted in his role as England captain coming under question from Fabio Capello. The England manager has this week come out making it clear England need a captain that can represent his country on a regular basis, something Ferdinand just can't promise at the moment. A more pressing concern though will be what affect Ferdinand's absence will have on United's end of season trophy drive. You can bet it will have a massive impact.

Ferguson admitted he was unsure as to when Ferdinand would be available again but made it clear the signs weren't overly promising.

"We are not looking at this as a short-term situation. He has not started training yet. We will be lucky to get him back for some part of the season," he said.

While Sir Alex will want to talk down the negative impact Ferdinand's absence will have on his side's bid to win the title, FA Cup and Champions League, but the fact is that without the experienced centre-back in the side, this team does look a little iffy at the back. It's been made even worse with the fact that Ferdinand's defensive partner Nemanja Vidic has also been having his own fitness issues over the past few weeks. The manager will have to use all his experience to make sure he can fill the gaps with the players that are available to him.