Real Madrid coach Zinedine Zidane said he cannot imagine Cristiano Ronaldo leaving the club next summer but will stay out of any contract negotiations between the player and club president Florentino Perez.

Ronaldo has let it be known that he has decided to leave the Bernabeu next summer. He has grown tired of a lack of progress during talks with Perez in which he is asking for a hefty pay-rise to around €50 million a year.

Sources have confirmed to ESPN FC that a return to Manchester United is Ronaldo's preferred option at the moment while not ruling out that the situation with Madrid can be resolved.

Zidane said on Thursday that the Portugal captain was not being distracted by the talk around his future and would focus on helping the team out of their current difficult spot.

Cristiano Ronaldo has let it be known that he would prefer to leave Real Madrid during the summer. Getty

"I do not imagine Cristiano anywhere else," Zidane said. "He is at his club where he should be. Everyone loves him here. I cannot see Madrid without Cristiano. I am most interested in the sporting side, and as always, in a difficult moment for the team, he is there.

"We know that people can talk and debate outside, but inside, Cristiano must just think about playing -- as he has always done."

Zidane said he had not spoken to Ronaldo about the contract stand-off with Perez, insisting that such matters should not intrude on a player's training and performance in games.

"I do not want to talk about the contract, or these things," Zidane said. "What I am most interested in is the pitch. That is what I talk to him about. Everything else he manages himself, I do not get into that. Everyone does what they think best. When I had difficult moments as a player, I just kept working hard and thinking the team would do good things soon."

Zidane is facing the first serious pressure of his two-year spell at Madrid with a run of just one win in five games entering Thursday's Copa del Rey quarterfinal first leg at Leganes. Madrid are fourth in La Liga, 19 points adrift of runaway leaders Barcelona.

With speculation increasing that Zidane could be fired by Perez unless the team's results turn around, the Frenchman said that he remains just focused on doing his work as best as he can.

Real Madrid's results have coach Zinedine Zidane's future in question. Angel Martinez/Real Madrid via Getty Images

"I don't think about that. I just go day to day," Zidane said. "I always say that and will not change. You know that. The situation is as it is today, but during the two years I have been here, when we won many things, I said the same.

"I know this club and just try and do my best day to day. If I thought that I [could not improve results], I would have to go. You can always improve. When you don't win, there is always a reason, but we cannot change or throw out everything. What we want is to win games. That will change the dynamic."

Karim Benzema was training with his teammates on Wednesday after apparently overcoming a hamstring problem, but captain Sergio Ramos remains out with a calf injury.

Zidane would not reveal his likely XI for Thursday, but suggested he would continue to use the Copa del Rey to give playing time to younger and back-up members of his squad.

That means Ronaldo and other senior stars such as Gareth Bale may again be rested.

"I am counting on all of them, as always," Zidane said. "They are all important for me, and will be until the end. You will see tomorrow how we manage it."