The European champions announced captain Terry would be sidelined for "weeks rather than months" following an MRI scan on the injury that forced him off during Sunday's game at Stamford Bridge.
The club added in a statement on, www.chelseafc.com: "Today's MRI scans on John Terry's right knee thankfully show no significant damage to the cruciate ligaments.
"Chelsea Football Club's medical team will conduct further tests over the next two or three days once the swelling has subsided to determine how long John will be out, but it will be a matter of weeks not months."
Any absence is nevertheless a huge blow for the Blues, with Terry having suffered the injury in his first game back after his domestic four-match racism ban.
The club had struggled badly in defence in his absence, slipping from first to third in the table. He will almost certainly miss their potentially decisive Champions League Group E game at Juventus, as well as crucial league matches against West Brom and Manchester City. He could even be a doubt for their Club World Cup trip to Japan early next month.
He said: "We managed to play games without him and we have players who will have a chance to impress. I have confidence. Obviously, it's a pity we will lose him again but we have a large squad and quality defenders to deal with that. It's important to have people who can step up. This is a chance for the others to shine and we are going to deal with his loss for him."
Terry has demonstrated supreme powers of recovery in the past, coming back from minor surgery on the same knee weeks ahead of schedule last season. Cech added: "He knows what it takes to come back in good shape and as soon as possible. He always heals well."