Madrid moved top of La Liga with a comfortable 2-0 home win over Celta Vigo on Saturday.
Hazard, who has had a miserable run with injuries, replaced Marco Asensio with 16 minutes remaining, completing all eight of his passes in a brief cameo.
He also came on for a short 13-minute stint in the draw at Elche on Wednesday and Zidane suggested that will be what happens initially with the forward, who has only started three La Liga games this season.
"We are going to go little by little," Zidane said about Hazard.
"Little by little, you have to recover feelings. We have to take it slowly and not force anything.
"He has to get back to his best and take it slowly. That is all it is."
Asensio, the man Hazard replaced, set up the early opening goal for Lucas Vazquez in the first half and then scored the second himself after the break.
Zidane was pleased for the Spain international, who also had an assist against Granada last month – his first goal involvement of what had been looking like a difficult individual season.
"I'm happy for Asensio," Zidane said.
"He has had a big injury and he is a lot better now and improving every time.
"I'm happy for him and it is like that with everyone else too."
Captain Karim Benzema was reasonably quiet, registering a 6.8 FC Rating with neither of his two shots finding the target.
But Zidane does not believe the 33-year-old needs a rest after playing in 15 of Madrid's 17 league matches so far.
"I don’t think he is tired," added Zidane. "I think he did well and I took him off so that another player could play.
"We are in a great spell. We are doing the right things and we have to continue like this.
"We played a complete game from the beginning to the end.
"We controlled the game well, we had a good balance, when it came to pressing up and getting the ball back, we did everything well.
"The feelings are good - out of nine games we won six and three draws."
Zidane's team moved one point ahead of Atletico Madrid at the summit, though have played three games more than their city rivals.