Manchester United manager Sir Alex Ferguson says Nemanja Vidic faces a longer spell out than first thought as he recovers from a calf injury.
The defender sustained the problem in the opening-day win over West Brom, but despite an initial prognosis of six weeks out, Vidic is no nearer a return.
"It's slow progress with Nemanja," revealed Ferguson.
"Calves can be troublesome. He's not done any training [and] he's not making any great progress at the moment."
United have won four straight league matches in Vidic's absence, with the likes of Phil Jones, Chris Smalling and Jonny Evans impressing in his stead.
But the Serbian remains a key part of Ferguson's squad and the Scot is hoping that the same fate which befell Bryan Robson does not strike his centre-half.
"I remember when Bryan Robson had calf trouble it kept him out for three months," said Ferguson.
"Hopefully it's not as long as that [but] calves can be troublesome."
United defend their 100% winning league record so far this season against Stoke on Saturday evening.