The Belgian has been out of action since undergoing ankle surgery in June.
He returned to competitive football this week with Belgium and is line to make an appearance for Chelsea against Leicester this weekend.
“He is ready, he is doing well and is ready to play,” Courtois told Sky Sports News. “But we cannot forget he was injured for four months, he had surgery.
“You cannot expect – if he plays on Saturday, which is up to the manager – if he gets minutes you will see his quality but maybe he is not at his top form like he was last season and you cannot forget that.
“You have to go little by little I think. We are excited to have him back and I was happy to have him on the pitch with me against Gibraltar and Greece.
“I hope we can see the best Eden Hazard very soon.”