Lorenzo Insigne's agent Vincenzo Pisacane said Napoli's contract offer for their star captain was not "acceptable" nor "appropriate", though he insisted it is not too late to sign a renewal.
Insigne, who emerged from the youth team of boyhood club Napoli in 2010, is set to become a free agent at the end of the season.
Negotiations over a new deal have proved fruitless so far amid reported interest from Serie A rivals Inter and Milan as well as La Liga giants Barcelona and Premier League quartet Tottenham, West Ham, Arsenal and Newcastle United.
Pisacane was asked about Insigne's future at Diego Armando Maradona Stadium.
"An offer has been made that is not considered acceptable, not considered appropriate," Pisacane told Canale 21. "But it doesn't mean we don't talk to each other anymore.
"Everyone plays their part, there are those who ask questions and those who request. The best thing is to talk to each other.
"I have read several times that Lorenzo has asked for the moon, but no request has ever been made. He feels Napoli as part of him, he perhaps holds Napoli excessively close. I struggle to find a player more attached to the shirt."
Insigne – a Euro 2020 winner with Italy – has continued to perform for Napoli, playing a key role in the team's strong start to 2021-22.
He has scored four goals and supplied five assists in Serie A this term as Napoli sit third in the standings, two points behind leaders Milan.
The 30-year-old ranks third for xG per 90 minutes (0.76) in Serie A, while he is also third for assists per 90 minutes (0.43).
Only Milan's Rafael Leao (21) has managed more shot-ending carries than Insigne (17) this season.
On the chances of Insigne remaining at Napoli, Pisacane added: "I can't give a percentage, I just can't. Marriages are made in two, therefore I think it's right to meet again, to talk about it and see if there's a possibility or not.
"I find it strange that we are in December, it's not too late but if I want something and I want to get it, I start working on it.
"Lorenzo has been a top player in the same team for many years and he always finds incentives to do better. I think it's very difficult to find a symbol like him. I think Lorenzo deserved a little more time."