The Spanish club reportedly sent a scout to monitor the 22-year-old during the Olympic Games in Rio earlier this month, during which he was the first-choice left-back in Brazil's gold medal-winning team, reports Xinhua.
"Everyone would be valued after such an achievement," the Atletico Mineiro player was quoted as saying by Brazilian news portal Sambafoot on Thursday.
"Nobody knows what the future holds, but for now I'm concentrating on winning the Brazilian Serie A championship and the Copa do Brasil."
Douglas has made 80 first-team appearances for Atletico Mineiro since joining the club from Italy's Udinese last year.
He made his full international debut in Brazil's 2-0 friendly victory over Panama in May.
