The 24-year-old sustained the injury to his right knee during the clash with QPR on Saturday.
Chelsea boss Andre Villas-Boas said: “It looks like a medial ligament injury, not so bad in terms of knee injuries.
“He will have the MRI scan tomorrow, I think hopefully he will avoid an operation.
“We could look at four weeks (out). We have to see the full extent of the injury.”
