The 19-year-old, who is rated as one of the brightest prospects in Spain, penned a new contract with Los Che in April 2018 in a deal which runs through until 2021.
Torres made his first team debut in November 2017 and has made 64 senior appearances for the club since, becoming a regular under Marcelino Garcia Toral and then Albert Celades.
The winger starred in the UEFA European Under-19 Championship in Armenia this year, netting both goals in a 2-0 final victory over Portugal.
Now, Sport Bild report that the winger has been identified by Borussia Dortmund as a long-term replacement for Jadon Sancho, who will eventually be sold according to the report, but they face competition from both Liverpool and Barcelona.