Manchester City boss Sven Goran Eriksson expects to be without Micah Richards for up to six weeks following his knee surgery.
Richards underwent surgery on a knee cartilage problem on Wednesday after suffering a recurrence of the injury.
It was feared that Richards could miss the rest of the season with the injury, but Eriksson is hopeful the England international will be back within six weeks.
"That's really bad news of course," Eriksson told Sky Sports News of Richards' injury.
"He was operated yesterday in London and I spoke to the medical people before and after the operation and they said before it would be six weeks and they confirmed after the operation he will be out around six weeks.
"But I heard from our medical people he is a good and quick healer so just to hope he is back before six weeks but we have to wait and see
"Bad news of course but unfortunately it happens."