Newcastle United launched a double raid on Napoli for Victor Osimhen and Fabian Ruiz in January.
According to Italian journalist Paolo Bargiggia, the Serie A side rejected a combined bid of €140 million (£117 million) for them.
Bargiggia told 1 Station Radio: “Napoli received offers from Newcastle for the two jewels Osimhen and Fabian Ruiz, around 40 million for the Spaniard; they could have reached even 100 for the former.
“Napoli turned them down and, the players themselves, were not convinced by the destination.
“The club has to renew the contract of Fabian Ruiz, who, at the moment, is one of the best in the squad and earns 1.5 million.
“My feeling is that if important clubs like Real Madrid show up, it will be hard to keep the player and match certain offers.”