Chelsea had been linked with a move for the player and now rumour has it that United are looking on with vivid interest.
But the powers that be at Napoli insist that they want to hang onto he Slovakian and have no interest in selling. Although this could be just in the hope of them getting a better deal.
"If we rejected the rumours about a friend like (Carlo) Ancelotti and Chelsea it is obvious that we also reject these," Napoli director of sport Riccardo Bigon told Radio Marte.
"We have no intention of giving away Marek."