The Welsh winger has been sidelined by a calf injury for just over a week, while Karim Benzema has not featured since hurting his knee in the Champions League quarter-final first leg at Atletico Madrid on April 14.
Ancelotti, whose side host relegation-threatened Almeria in La Liga on Wednesday, said Bale was due to return to training with his team mates on Thursday and Benzema would probably be back with them on Sunday.
Their return will boost Real Madrid for what Ancelotti called a “life and death” couple of weeks, when in addition to the Juve tie in Europe’s elite club competition they play at Sevilla and host Valencia in La Liga.
Real could find themselves five points behind Barca when they run out at the Bernabeu to face Almeria on Wednesday, with the leaders hosting Getafe at the Nou Camp later on Tuesday.
Barca have 81 points with five games left, with Real on 79, seven ahead of champions Atletico, who play at Villarreal on Wednesday.
“It’s a time of the season when all the games are life and death for every team.” Ancelotti said.
“We have to prepare this match (against Almeria) bearing in mind that it comes before a very difficult and very demanding run of games.
“We have a tough calendar, the matches are very, very difficult.
“We have confidence we can play well because the team is in good shape, it’s fresh and can compete in all the games.
“We are not thinking about whether Barca will slip up we just have to focus on the matches we have.”
Second-placed Real are two points behind Barcelona, who host mid-table Getafe on Tuesday, with five matches remaining.
Real’s Mexico striker Javier Hernandez, who is on a season-long loan from Manchester United, has been on good form in the absence of Bale and Benzema but will almost certainly drop back to the bench once they are fit.
Ancelotti said he would discuss the issue of making Hernandez’s loan move permanent with Real officials at the end of the season.