Fofana has been on the sidelines for the past few weeks with a hamstring injury while Badiashile recently suffered a setback of his own.
Speaking in his pre-match presser, Maresca said that the French duo are still out and could be on the sidelines for a long period of time.
He said: "Both they are still out and both will still be out for a long period."
In the absence of the duo, Tosin Adarabioyo has got the opportunity to partner Levi Colwill in the heart of the defence for the league games.
The Englishman will be aiming to continue the good form such that he can keep his starting spot ahead of Axel Disasi in the coming weeks.
Chelsea have exceeded expectations this campaign and they are presently just two points behind leaders Liverpool, who have a game in hand.