The Argentine duo started their careers with the Buenos Aires club, before completing big-money transfers to La Liga with Valencia and Barcelona respectively and going on to enjoy relative success in Europe.
However, they have both been tipped to leave the Lisbon side, having failed to secure much first-team football over the past season, but according to Mancusi, they will not be moving back to their former club.
"I was the one to contact them but they said they did not to want to return to River Plate," Mancusi told Radio La Red.
"The situation with Aimar and Saviola, but also Martin Demichelis and Andres D'Alessandro is clear; at the present time, they want to pursue careers with their respective clubs."
River were promoted back to the Primera Division last week at the first time of asking, following their relegation last year.