Chelsea captain John Terry could miss all of the side's fixtures over the festive period due to his knee injury.
The Blues' interim manager Rafael Benitez has admitted that Terry's injury is "quite complicated" and could not guarantee that he will be back in action anytime soon.
Terry, who was scheduled to return almost two weeks ago, has trained without a ball this week, but is still not ready to return to full first-team training.
"It's one step forward, one step back. The knee is quite complicated," said Benitez.
"At least he's now on the pitch - that is positive news - but we cannot say, we cannot predict how long it will take."
When asked if Terry would return in the next fortnight, Benitez said: "I hope so but I am not a doctor. So I cannot guarantee anything."
Terry will definitely miss Chelsea's clash with Aston Villa this Sunday.
