Chelsea have confirmed John Terry has undergone knee surgery which will keep him out of action for three weeks.

The Blues have also revealed Ashley Cole faces up to a month on the sidelines with an ankle injury he sustained on international duty.

Terry has been forced to go under the knife to cure the knee problem which forced him to miss England's 2-1 defeat to Russia in midweek.

The England skipper is now set to be sidelined for up to three weeks and he faces a race against time to be fit for England's crucial Euro 2008 qualifier with Croatia.

Cole also faces a battle to make the Croatia tie after suffering an ankle injury in the 3-0 win over Estonia.

The news is a double blow for Blues boss Avram Grant as it means both players will miss key Premier League and UEFA Champions League games for Chelsea.