Coach Carlo Ancelotti announced that the Welshman would make his comeback from the calf injury he suffered against Granada in January, but the involvement of fellow forward Cristiano Ronaldo is up in the air.
The hosts are looking to bounce back from the dropped points in the 1-1 against Athletic Bilbao last time out in the Primera Division and the perceived injustice of Ronaldo's red card.
The Portugal international was banned for three matches for the dismissal, but could yet feature at the weekend pending the outcome of an appeal.
Madrid responded with a 3-0 Copa del Rey win over league leaders Atletico Madrid, when Bale was expected to play but did not.
Asked on Friday about Bale, Ancelotti said: "Tomorrow he will play."
The Italian told the press conference he was "not interested" in talking about Ronaldo's situation.
Madrid go into the weekend level on points with second-placed Barcelona and three behind Atletico, and Ancelotti said his side would not be drained following their midweek exertions against their city rivals.
"I have confidence that the players are ready to play a game with the same intensity," he said.
Villarreal striker Jeremy Perbet insists his side, who are fighting for a Champions League place, will head to Real Madrid on Saturday full of enthusiasm rather than trepidation.
"We are facing one of the most interesting games to play and we will do it with great gusto and with great enthusiasm," Perbet said on the club website.
"It is sure to be a great game and we'll see how it goes. We know it will be a tough game. The key is to keep a clean sheet early on and be strong in defence.
"It is difficult, but we'll try. From there, we're a team that are playing well, attacking well and have shown that this season. Therefore we will try to do well in the Bernabeu and get something positive."