The Belgium international missed his country’s international fixtures this week after testing positive for Covid-19, which also prevented him from playing against Valencia.
Saturday's clash sees the second-placed side host the fourth-placed Blancos, who will leapfrog their opponents with a victory.
Hazard’s only league outing for Madrid this season came in a thumping 4-1 victory over Huesca at the end of October. In that fixture, he played for an hour and scored the opening goal after being set up by Fede Valverde. Previously, he had been out with a muscular injury.
Hazard, who has also featured in two Champions League matches this season, will be back for the weekend, however.
“The evil is almost gone. I think he’ll be ready for the trip to Villarreal,” Courtois said. “He was extremely disappointed not to be able to go to Valencia and then to miss the international matches.
Belgium just need to avoid defeat to Denmark at home on Wednesday progress to the Nations League Finals. It is a similar scenario to the previous campaign, though on that occasion they erred in a 5-2 loss to Switzerland.
“In football, you should not be afraid to have the ambition to win titles,” he said. “At the time, we knew we could lose by two goal and we probably relaxed. That’s unforgivable at international level.
“We know Denmark are a top level opponent. They showed it by going to win at Wembley. They can come and win here and that’s why we must prepare well.
“Most of their players play in the Premier League, Bundesliga or La Liga. It will be very complicated but we know what we have to do.
“We’re a team that concedes few goals. We fought for each other against England and we can score at any time.”