He added he hopes Neymar will one day join him at Real amid ongoing rumours that the £200 million superstar is unhappy at Paris Saint-Germain, per Sport: "Neymar is a crack. He knows what he's doing, he's a great player and he will always be welcome at Real Madrid. I hope he comes, but he's happy at his club."
Neymar, 25, only joined PSG from Real's rivals Barcelona in the summer, but there have been numerous reports recently indicating he is unsettled at the Parc des Princes.
Joaquim Piera of Sport recently explained Neymar is "not comfortable" at PSG, lacks motivation for Ligue 1 due to its uncompetitive nature and lacks belief in manager Unai Emery.
The former Santos man recently denied the claims in a tearful press conference following Brazil's friendly defeat of Japan.
He hit back at the accusations, including his apparent rift with Emery and team-mate Edinson Cavani, per Reuters:
"I don't like whispers and stories so it's better that you hear it from the horse's mouth. I don't have any problems at PSG, the only thing that bothers me is the pressure from the media. I‘m a guy who likes to win, I like winning titles and that's why I came to PSG.
"I‘m very happy, I‘m motivated. They are inventing stories which aren't true, I don't have any problems with Edinson Cavani or with my coach. I came to help and to be happy, I didn't come to upset anyone or cause trouble."
Casemiro is not the first Real star to say Neymar would be welcome at the Bernabeu.
And there is little doubt Neymar would be a stunning addition to the current Real squad, not least as he could be the perfect successor to 32-year-old Cristiano Ronaldo.