The Black Cats reportedly attempted to sign him last year but the Portuguese club clung onto their £20m-rated winger.
However, according to Diario de Noticias, Benfica will look to cash in on the Argentinean when the transfer window opens.
They are trying to raise money to fund their own recruitment drive and believe they can pocket a decent sum by selling the 26-year-old.
Salvio has scored four league goals in 24 outings this term, while also starring in the Champions League, where he has notched three times in eight appearances.
Sunderland are currently embroiled in a relegation battle so it is difficult for them to plan their summer signings as they do not know which league they will be competing in next term.