Real Madrid coach Zinedine Zidane is facing a full-back shortage after the club confirmed that left-sided defender Marcelo has been sidelined by a hamstring strain.

The Brazil international played the second half of Madrid's 2-2 draw with Club Brugge in the Champions League on Tuesday, coming on as a substitute for Nacho.

After the game, Nacho was taken to hospital for tests on his left knee, which revealed ligament damage and he is expected to be ruled out until Christmas while he recovers.

Zidane is unable to call upon France international Ferland Mendy to provide cover at left-back for Madrid's clash with Granada on Saturday as he is in recovery from a thigh injury.

Los Blancos' boss was even asked in his pre-match news conference whether Gareth Bale could deputise given his experience of playing in deeper roles over the years.

"The truth is that I have not thought of that at all," said Zidane, before pointing to right-footed Brazilian defender Eder Militao as a possible solution to the problem.

"We have other possibilities before that. [Militao] may be an alternative. He is a defender, he has played in this position, it is a possibility."

Zidane faced questions about goalkeeper Thibaut Courtois, who was jeered by Madrid supporters before being replaced at half-time against Brugge by Alphonse Areola.

The club put out a statement to say that Courtois was ill during the match, to counter reports that he was replaced due to poor performance and anxiety.

Zidane offered words of support for Courtois, who kept three consecutive clean sheets prior to the Brugge game, but stopped short of confirming who would start in goal against Granada. 

"He was bad, yes," Zidane said of Courtois. "He was disturbed. It can happen, but a player can play in spite of that. But at the break, he was no longer able to play.

"Whistles, whether unfair or not, are like that. He is strong mentally. We know, internally, that the fault is collective in the first period against Brugge.

"I have 25 players, I count on each one of them. Thibaut Courtois is one of them. People can talk, have their opinion, about what happened on Tuesday. But the three games before, it was Courtois in goal and we did not concede any goals.

"No one is indisputable, neither Courtois nor anyone. [Areola] is a great keeper, like Thibaut. He is very good, and that's it. We have two good goalkeepers who play and that's it."