The 27-year-old raptured cruciate knee ligaments during the FA Cup clash with Southend in the midweek.
Chelsea captain John Terry added: “We’re all gutted for him. We’re all behind Coley to get fit as soon as possible. No-one will be more hurt at missing games through injury than Joe.
“He’s going to be a big miss for us and I keep on saying he’s the one who really opens things up in tight moments.”
