Chelsea midfielder Michael Essien might not play again this season.
He suffered a cruciate knee ligament injury during Ghana's defeat to Libya last Friday and now faces at least six months out.
The former Lyon star is now expected to undergo surgery but even if he returns in March as predicted, Chelsea fear it will take a further six weeks to get him match fit.
A Chelsea spokesman confirmed: "He has ruptured his anterior cruciate ligament and will undergo an operation as soon as the majority of the swelling has subsided. We expect this to happen in a week's time.
"In the meantime Michael has started rehab in the aqua therapy centre at Cobham which will improve the condition of the knee prior to surgery. A return to full fitness is not expected for several months."
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