The Black Cats shot-stopper is one of a number of Belgium internationals currently setting the Premier League alight.
After establishing himself as number one at the Stadium of Light, Mignolet has become one of the most consistent performers in the English top flight.
His efforts have not gone unnoticed, with transfer speculation building steadily heading into the summer.
The 24-year-old's representative has, however, sought to distance his client from speculation suggesting a switch to Serie A could be on the cards.
Kristof Vandersmissen told tuttomercatoweb.com: "Napoli interested in Mignolet? I have also read this news, but personally I have had no contact with Napoli or any other Italian clubs.
"Simon has a contract for another two years with Sunderland and it's normal that clubs are interested. That is proof that he is doing well.
"However, I repeat, he has a contract with Sunderland."