Atletico Madrid midfielder Saul Niguez has said playing for rivals Real Madrid would be "unthinkable" ahead of facing them at the Bernabeu on Saturday.
The 23-year-old played for Los Blancos at youth level but left after being the victim of bullying, but he has since become a key player for Diego Simeone at Atletico.
"It would be very difficult, unthinkable," he told Spanish radio station Cadena Ser's "El Larguero." Asked if there was any chance, he added: "No way."
Saul signed a new contract with Atletico during the summer which will keep him at the club until 2026 and said he accepted the offer without hesitation.
"They didn't call me personally but when Atletico offered me the renewal, I took it without negotiating or anything," he said. "I am calm here. I don't think there's too much of a difference with Barcelona. In fact, [Antoine] Griezmann stayed here."
Atletico have made a slow start to the La Liga season but after Barcelona and Real Madrid lost in midweek they moved up to third and sit two points off top.
"It's a very equal league," he said. "It wasn't normal that Barcelona won almost all of their games last year. The smaller teams can compete with the big one and that makes it more beautiful."
Saul said that he does not feel the same connection with Atletico's Wanda Metropolitano stadium as he did to the Vicente Calderon.
"The experience I lived there, I wouldn't change it for anything," he said. "The communion I felt with the fans and the way it rained. I don't feel the union with the fans as much now. Excuse me if I have offended anyone but I stick with the Calderon.
"Sincerely, when I talk to opponents they say to me that they don't feel the pressure the same way as at the Vicente Calderon," he said.