However, the visitors' chances of overcoming a 2-1 first-leg deficit were handed a huge boost as Bayern boss Carlo Ancelotti confirmed top scorer Robert Lewandowski will be fit to start.
"They've got a brilliant squad". The first leg has already been played and we know the problems Bayern will create, they'll make it hard until the referee blows for full time.
Madrid coach Zidane is also a fan and said: "Lewandowski is a real number nine and a bonus for Bayern". Lewandowski was even training with the team.
"I think they both have a good chance to play." added a hopeful Ancelotti.
"I hope it is nothing and in a few days he can be with us again". "Hopefully we have corrected the mistakes that we made in the first leg". If Hummels or Boateng don't make it, and emergency defensive pairing of Joshua Kimmich and David Alaba could be required.
Madrid have a foot in the semi-finals following their 2-1 first-leg win at Bayern Munich and Welsh star Bale talked up the European champions heading into Tuesday's return fixture.
Gareth Bale is a doubt for Los Blancos, with a calf injury.
Bale's latest injury could rule him out of Sunday's La Liga match with Barcelona. We have a good result but we will continue in the same way and take nothing for granted. Hopefully he will be back for the "clasico" (against Barcelona) but it's not certain yet. Madrid was eventually eliminated 4-3 on aggregate after a 2-2 draw in Vigo.
34 - Real Madrid have not failed to score for their past 34 Champions League home games and have won 34 out of 40 at the Santiago Bernabeu since 2010-11 (D4 L2). "It looks tough for him, just 77 minutes, it's not much. But we have a lot of important games and tomorrow we'll see what happen".
Gareth Bale has admitted that the Champions League is "the competition" for Real Madrid this season, describing it as "the essence" of the club.
Bayern Munich conceded 12 shots on target in the first leg against Real, more than in any other Champions League game since Opta analysis began on the competition in 2003/04. "The first leg is already over".
A contrasting spot-kick, with Bayern Munich midfielder Arturo Vidal blazing wastefully over, gave Real Madrid a sniff of turning around their match at the Allianz Arena.
All five previous teams winning 2-1 away from home in the first leg of their Champions League knockout tie have progressed to the next round. "It will be very hard in Madrid but we still have confidence".
"We'll go there and try to turn the tide", Bayern defender Philipp Lahm said.
Bayern will be hoping luck is on their side on Tuesday evening.