Jose Bosingwa ia out of action for at least three months.
Bossy has not played for the Blues since the defeat to Aston Villa in October.
He has now had an operation on his left knee and won't be back until the end of January.
On the other side of the pitch Ashley Cole is still struggling and will be missing for several more weks.
The club have revealed that he won't undergo an operation on his shin.
Chelsea said: "Ashley Cole is suffering from an aggravation of a depressed fracture of the tibia, originally picked up against Atletico Madrid at Stamford Bridge. The injury will not require surgery."
I their places will come either Branislav Ivanovic or Paulo Ferrieria, probably both.
Top of the table Chelsea return to league action on Saturday week with a home game against Wolverhampton Wandererers.
Hopefully Diddier Drogba will be fit for that game following his withdrawal from the Ivory Coast game against Guinea on Saturday.
He was kicked in the chest by Jonny Evans in the 1-0 win over Manchester United on Sunday and is getting treatment for it.
Chelsea are working under the assumption that they will be allowd to buy and sell in January.
French winger Franck Ribery is the main target from Bayern Munich.