With Napoli having missed out on Champions League football and already completed the big-money addition of Victor Osimhen, there is the suggestion that they are open to parting ways with Koulibaly.
Speaking to Sky Italia, De Laurentiis said: "Kalidou is a wonderful person and of course it'd be sad to lose him. Everything has a time and a place, even when it comes to going our separate ways.
"Having said that, we don't have €90m (£81m) on the table and in any case, it takes two to separate."
The 29-year-old still has three years remaining on his contract.