The Spain international was signed from Barcelona for around £30m in the summer, and the Blues boss thinks that the ex-Arsenal midfielder's ability to play in a number of positions will be vital to his team this year.
The Mirror quotes him as saying: "One of the reasons Cesc is so important for us now is because he can play in any position.
"Even at Barcelona he was playing so many times as a [striker], their style of [a number] nine. He sometimes played on the left wing too."
Chelsea are currently top of the Premier League, and travel to Manchester City this afternoon.