Michael Essien could be back in action by the end of December as the Ghana international makes steady progress in his recovery from knee surgery.Essien's rehabilitation has been going smoothly with Chelsea coach Andre Villas-Boas revealing that the midfielder's comeback is edging closer as he expects the player by the end of the year."Essien is making good progress and we're thinking end of December," the Chelsea manager said.The Chelsea midfielder ruptured his anterior cruciate ligament at the start of pre-season training