Manchester United manager Sir Alex Ferguson fears that Rio Ferdinand and Nemanja Vidic could both miss Saturday's Premier League clash with Blackburn Rovers.
Neither defender has been able to train this week while captain Gary Neville definitely misses out after being handed a three-match ban for his red card in the midweek Carling Cup win at Barnsley.
Ferguson admitted:"Rio and Vida are both doubts and we will just have to see what happens.
"With Gary Neville suspended, we are hoping that we can get one or two fit, but it looks like an uphill battle at the moment.
"Vidic has been bothered with his calf for a few weeks now and we have sent him to a specialist to try to get to the bottom of it.
"We will see what happens in training today, though, because Ferdinand and Vidic will both want to play after the disappointment of last Sunday.
"Ryan Giggs has a knock, so he is a doubt, while Darren Fletcher only returned to training on Thursday for the first time since the international break.
"He won't be fit for Saturday, but we are hopeful that, with ten days training, he will be ok for the game at Chelsea next week."