Napoli president Aurelio De Laurentiis has spoken of his anger towards Kalidou Koulibaly, who suggested recently the club were showing little interest in keeping him.
Last week, Koulibaly claimed he had offers from other clubs on the table - with Chelsea reportedly one of those - and that talks of a new deal with Napoli were "at a dead end".
His remarks have infuriated the outspoken De Laurentiis, who claims the club have lost out on millions in merchandising revenue as a result.
"I had thought Koulibaly was a good man," said the president, in quotes reported by Corriere dello Sport. "The moment I realise you and your agent haven't read the contracts properly before signing them, I cannot tolerate that.
"Napoli were about to sign new commercial deals to use Koulibaly's image, but his statements cancelled those opportunities. His jersey cannot be sold now.
"He created damages worth millions of Euros and I have specialists studying the issue now.
"I'm disappointed he didn't just call me and ask if Napoli intended to sell Koulibaly or not. I don't bother other clubs, approaching their players who are under contract.
"If we discovered that Chelsea were behind this, then we could sue them for damages too. Koulibaly is 24 years old, he is not a kid. We stood by him when he was jeered in his first season.
"Out of respect for the club and [coach Maurizio] Sarri, he should not have made those statements. Apologising to the fans is not enough. He will continue working for us for the three years on his contract and maybe many more until he's paid off the damages to Napoli."
Meanwhile, amid speculation star striker Gonzalo Higuain could be set to depart, De Laurentiis is confident the Argentinian will not let the club down after all it has done for him.
"So far I have not received offers for Higuain that match the clause, EUR94.375million, and assuming a club exists that would offer that money, he knows perfectly well that he could earn more elsewhere, but not have the same spotlight," De Laurentiis said.
"Gonzalo is a good man and Napoli will become for him what it was for Maradona. Diego entered world football history thanks to Napoli.
"If Higuain were to listen to the siren song of European giants, he'd have to take into account that in certain contexts you only play if you do well. Nobody will wait for you there.
"He is young and has a family that believes in healthy values. I have already put the money on the table to improve his contract, which is what he deserves. I have the feeling Pipita will not betray us."