Essien has been out with a cruciate ligament, he suffered while on international duty for Ghana in September.
He told Chelsea TV: “I think with these injuries you can’t really give it a time, it can be shorter or longer, the time is not that important.
“The most important is for me to get back stronger. If I come back early fine but if it takes a bit of time, fine.
“At the moment everything is going well, I am recovering very well and it won’t be long before I can go outside and start running a bit.”