The shot-stopper is reportedly unhappy with life at his current club, but his Spain colleague believes a move to the Camp Nou side is very unlikely
Valdes has said he does not want to extend his current contract until 2014 and could therefore be on his way out of Barca. Casillas, 31, on the other hand has lost his starting berth at Madrid and has been linked with a move away from the Blancos, too.
Nevertheless, Xavi believes it is unlikely Casillas will leave the Santiago Bernabeu side for their arch-rivals.
"I feel bad for Iker that he has ended up on the bench and I think it's unfair. I do not think that he will come to Barcelona, though," Xavi told El Mundo Deportivo.
"He's a real Madridista. We cannot look beyond that. I would welcome him with open arms, but I cannot see it happen to be honest."
The influential midfielder then went on to stress he does not expect Valdes to change his plans for the future, while praising the goalkeeper for his fine performances.
"I know Victor pretty well and I do not think that he will have second thoughts. He is an extraordinary person and I am sad that he will leave," he added.
"He is not only a friend, but also a real leader. He has probably received the worst treatment in the media I have ever seen in my career. He has always overcome criticism. The harsher the criticism, the better his performances."
The 31-year-old shot-stopper has made close to 500 official appearances for Barcelona since making his debut in 2002-03.