Carlo Ancelotti has confirmed Casemiro is closing in on a transfer to Manchester United, with the Real Madrid midfielder wanting a fresh challenge.
News broke on Thursday that United were confident of striking a deal for the 30-year-old, who has been a mainstay of Madrid's midfield in recent years.
It has been widely reported that a fee in the region of £51million (€60m) has been agreed for the Brazil international, with add-ons potentially taking the deal to £59.4m (€70m).
Casemiro trained with Real Madrid's squad on Friday ahead of Saturday's LaLiga game against Celta Vigo, but in his pre-match press conference, Ancelotti confirmed a transfer is in the works.
He said: "We've spoken this morning, he wants to try a new challenge, a new opportunity. I understand this, also the club does.
"Because of what he has done in this club, his desire and due to everything he has done for this team, we need to be respectful of this.
"There are negotiations between the clubs, he is still a Real Madrid player but it looks like he is now willing to depart. If he is departing we have a lot of resources to replace him."
Asked if he had attempted to sway Casemiro's decision to leave, Ancelotti replied: "No.
"I've always talked a lot with him in my second time at Real Madrid. I just listened to his desire, I think there's no turning back. This is what he wants.
"If everything goes well, the negotiations go well, we just need to wish him the very best.
"It is difficult to speak anyway because I don't know what's going to happen in the next few hours, if he's staying or leaving, but if he leaves we will always be thankful to him because he's been a wonderful player with us."
Only nine days ago, Casemiro was named man of the match as Madrid saw off Eintracht Frankfurt to win the Super Cup.
Though Ancelotti knows Madrid are set to lose a key player, he does not believe the task at hand for Los Blancos this season changes.
"There were some rumours and yesterday I realised this could happen but the plans are not going to change, Real Madrid's plans will always be to fight until the end, compete in every single competition for every single title, and we will do it with or without Casemiro," he added.
"Everybody knows he has been a player for us, and we love the kind of guy that he is."
Should his move to Old Trafford go through over the weekend, Casemiro could make his United debut on Monday against arch-rivals Liverpool, although he still has to undergo a medical and sort his visa.
United have lost their opening two Premier League games, going down 2-1 at home to Brighton and Hove Albion before suffering a humiliating 4-0 defeat to Brentford.