Cole sustained the injury in Chelsea's 4-1 FA Cup win over Southend last week, and has undergone surgery on Saturday.

"We have had some bad news about Joe Cole, who has a knee injury and will be out for some time," said Chelsea boss Luiz Felipe Scolari.

"It is a big disappointment for Joe and a big loss to the squad. We wish him the best recovery."

The England international faces six months out and will definitely miss the World Cup qualifier against Ukraine in April.

Cole, 27, is the second Chelsea player to suffer a serious knee injury this term, following a similar blow to Ghanaian midfielder Michael Essien.