Napoli have set Arek Milik a 20-day deadline to sign a new contract.
Gazzetta dello Sport says Napoli president Aurelio del Laurentiis has told the Pole to sign the deal tabled or he will be sold. Milik's current contract has just over 12 months to run.
Should the contract offered be snubbed, Milik will be put up for sale at €50m.
ADL has offered a contract worth €5m-a-year, with a buyout clause of €100m. Milik's agent David Pantak is seeking to reduce the option to €50m.
Tottenham boss Jose Mourinho is watching developments closely.