Casemiro would welcome the arrival of Manchester United star Paul Pogba at Real Madrid despite the competition he would bring to their midfield.
The France international has been linked with a move to the Santiago Bernabeu and his recent comments, in which he said it would be "a dream" to play for Zinedine Zidane's club following his compatriot's return to the Spanish capital, further fuelled speculation.
United manager Ole Gunnar Solskjaer expects Pogba to remain at United, but Casemiro would be in favour of him moving to Madrid even though it could potentially put his place in the team in jeopardy.
"[Pogba]'s a world class player. [He] can play in any team," Casemiro is quoted as saying by AS.
"If he comes to Madrid he would be warmly welcomed, we know he is a great player.
"For sure he is currently thinking about his next Champions League game, that is type of person he is. We must respect Man United also.
"I always say that Madrid must have the best players, as this is the best club in the world. But it is not for me to say which players should be signed."
Casemiro would also unsurprisingly be in favour of international team-mate Neymar trading Paris Saint-Germain for Madrid, adding: "Neymar is a great player and it would be great if he came here. But this is a question for the president, and for Neymar himself.
"You'd have to ask him if he wants to come. He said recently he was happy in Paris, so we must respect him, and his club.
"But a great player like him would be an automatic pick in any team."
Casemiro moved to defend team-mates Marcelo and Gareth Bale, with his fellow Brazilian being criticised for his performances this season and the Welshman being jeered by his own fans.
"We cannot talk about Marcelo's season because we have all failed. He is a great person and player," he said.
"When one of us are whistled, then we are all whistled."