“Bellingham is an important player for us, like Cortois, like Militao” Ancelotti told reporters.
“To play without Bellingham is difficult of course, but we have (Brahim) Diaz and other players that can replace him.”
Madrid sit five clear after Saturday’s win, having lost just once in 24 league games all season.
Midfielder Toni Kroos, who has won four Champions Leagues with Real, said “I don’t know if we are the favourites, but we are in a good position to win the title.”
“But as we’ve seen in previous years, a bad day is enough to be booted out. It’s a difficult title to win.”
‘Not outsiders’
Earlier on Monday, RB Leipzig coach Marco Rose shut down suggestions the hosts would be outsiders in Tuesday’s match, saying his side were “not afraid” of Real Madrid.
“The topic of us being outsiders wasn’t worth considering for me at all, because football games need to actually be played,” Rose told reporters on Monday ahead of the first leg of the last-16 tie.
“Incredible things have happened in football.”
Leipzig are struggling for form ahead of the visit of La Liga leaders Madrid, having won just one of five games since Christmas to slide to fifth in the Bundesliga.
Despite this, Rose said his side had “no fear” against the 14-time European champions.
“We are not afraid at all, we’re looking forward to it.
“It’s what we want. It’s what we worked hard for last season and what we fought for in the group stage.”
Leipzig goalkeeper Peter Gulacsi said Real still had “incredible quality, even if Jude (Bellingham) is injured”.
“I could name their entire midfield.”
Rose, who coached Bellingham at Borussia Dortmund during the 2021-22 season, did not rule out the England international making a surprise appearance despite the injury.
“I’ll only believe that Jude is ruled out when I don’t see him in the stadium tomorrow.
“I know Jude, I know he’ll do everything to play a Champions League game, even if it means that today he’s searching around to try and be treated by a doctor here.
“I’ve read plenty (about his absence), but we’ll see.”
Bellingham moved from Dortmund to Madrid in the summer and has become a crucial part of Carlo Ancelotti’s side, topping the scoring charts with 16 goals so far in the league.
“The way Jude is playing at the moment, at the 10 position, makes him one of the best in the world,” said Rose.
“Jude is at the right club… I’m not surprised he’s hit the ground running like he has in Madrid, I am maybe a little surprised by how many goals he scored.
“I had him for one year, a great lad, unbelievable mentality, classy footballer who is now making more steps forward.”
© Agence France-Presse
Photo: Twitter @MadridXtra