Failure to win any silverware is set to see the former Milan coach fired just 12 months after winning the Double.
"I don't know if he has to win the title to stay at Chelsea," said Ranieri.
"I think Ancelotti is doing a very good job - you can't win everything every year.
"Last year, he won the Double. Nobody had done the Double at Chelsea before. Ancelotti is a great coach - he has proved it over the years. I hope he is given the chance to stay at Chelsea and win more trophies in the future."