Reports throughout the summer have suggested that Vidal is a big-money target for Louis van Gaal's United, with talk of a £45million bid dominating the transfer window headlines.
The 27-year-old signed a new contract earlier this year to keep him at Juventus until 2018 and the Serie A champions have previously stated he would only be sold if he asked for a move.
German champions Bayern Munich have also been claimed to be keen on the Chile international, but Marotta says no bids have been received.
"The negotiation has mostly been fuelled by the media. There has been talk of Manchester United and Bayern Munich interested in him but the facts are different," he said.
"He never asked to leave because he had recently extended his contract with us and there were no bids. There are all the conditions why Arturo stays here."