"It would sound very opportunistic to say that Barca need me now," the veteran defender told Sport.
"I always said that I left because I saw things were not the way I thought they should be.
"You never want to see everything that [has] ended up happening since I left. I've said that when Barca need me and want me, I would be at their disposal regardless of where I am. The affection, love and respect I have for this club is too much.
"If Barca think they need me, they just have to call me. I still think I can contribute anywhere, but more at Barca because of the number of young players that they have now."
The 38-year-old, whose Barca career came to an end in 2016, left Sao Paulo after spells with Juventus and Paris Saint-Germain.
He also added another honour to his name with Olympic gold at Tokyo 2020.
Despite his age, he has reiterated that he has no plans to retire and intends to continue at the top level, adding: "I always look for a club that allows me to compete with the greats, fight for titles and be decisive wherever I am.
"I do not consider another scenario that is not this. It was for this reason that I chose Sevilla, Barcelona, and all the places where I went. I want to bring a winning, fighting and conscious mentality wherever I go."
Ronald Koeman's side face a difficult test on Sunday (16 October) when they host Valencia, who currently sit one position above Barcelona in the La Liga table.
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