The Spanish right-back believes he and the 31-year-old will get over their problems in time but admits they are now on strictly professional terms
The 30-year-old was one of Jose Mourinho's fiercest allies in the Blancos dressing room, while the Portuguese coach had a well-publicised row with the legendary goalkeeper.
And Arbeloa insists that he and his skipper will get over their problems in time but claims the former Inter coach cannot be blamed for anything.
"It is clear. Maybe Casillas and I no longer have the unity we used to have but it is still a professional relationship," he told Cope.
"Someday, it will get better with Casillas. We'll get together and say what we have to say to each other face to face.
"The problems between two people are between two people - not with a third. It seems sacrilege to speak well of Mourinho, but I do it from having worked of him every day.
"The Real Madrid dressing room cannot be a nursery."
Paris Saint-Germain boss Carlo Ancelotti has been strongly linked with a move to replace Mourinho and Arbeloa has been impressed with the Italian's career to date.
The defender added: "Carlo Ancelotti has done well with every club at which he has been. If he comes, I'd be delighted of course."