Hazard is yet to make his first appearance for the Premier League champions this season having undergone ankle surgery during the summer break, but he is thought to be close to a return to full fitness.
Willian and Pedro have filled in for the Belgian during his absence, helping Chelsea record back-to-back victories over Tottenham Hotspur and Everton, and Courtois warned that his compatriot would not walk straight back into the team.
"You will always miss a player like Eden but we have handled it very well and it will be hard for him to come back into the team. He is someone who has done so many amazing things for us already," Courtois told reporters.
"We are building a strong team at Chelsea and were champions last season and hopefully we can do the same this year."
Chelsea sit sixth in the Premier League table after three games of the season.