Manchester City are fearing the worst as they await test results on the knee injury suffered by Micah Richards in the victory over Swansea City yesterday.
The England defender was stretchered off after going to ground clutching his knee in the second half.
The club fear that he could be out for months, with Roberto Mancini telling the Daily Mail: "It is probably a bad one but we hope for the best."
Richards has only just comeback from a long-term ankle injury and needed oxygen as he left the pitch.
City won the game 1-0 thanks to a Carlos Tevez goal.