On left-sided France defender Silvestre, Perrin said: "His agent has made a discreet appeal to us.
Heinze lost his attempt to force United to allow him to move to Premier League rivals Liverpool.
The 29-year-old claimed the Red Devils had given him written permission to pursue a transfer to another club for a fee of £6.8m, but a Premier League arbitration panel ruled against him.
Heinze is set to appeal against the decision but Perrin could make a move.
"We are waiting for a response about Gabriel Heinze," he said. "He really has the profile of the player we are looking for."