The Argentina international is reportedly on his way back to Benfica, after spending last season on loan at the Estadio da Luz, and could complete a transfer on Tuesday
The forward, 22, has been strongly linked with a summer departure from the Vicente Calderon, having failed to establish himself in the club's first team since his arrival two years ago.
According to AS, Salvio did not fly out with the rest of Atletico's squad to Colombia on Monday as he was taking care of the final details regarding a transfer to Benfica, whom he represented on loan during the 2010-11 campaign.
The Argentina international is expected to undergo a routine medical examination in Lisbon on Tuesday and pen a reported five-year contract, which will keep him at the Estadio da Luz until 2017.
Salvio, who came on as a late substitute in Atletico's 3-0 victory against Athletic Bilbao in the Europa League final, will reportedly cost Benfica a fee in the region of €10 million.