The club's £18million summer signing from CSKA Moscow has yet to kick a ball in anger in the Premier League, but the Chelsea coach is confident the injury can be controlled and improved without the need for an operation.
"Now, at the moment, we don't think he needs surgery," said Ancelotti.
"He's working with the team. Yesterday he worked with us.
"We have to control the situation. For the moment, he's not very well but he is improving. Next week we have to control his body. If he has improved, he can start to play matches again.
"He is improving. He didn't play with the national team because he's not fit now, but he is improving. At the moment, he doesn't need surgery."