Antonio Conte identified Koulibaly as his first-choice target last summer but Chelsea found themselves scared off by Napoli’s £60million valuation of the Senegal international.
The Blues remain in the market for defensive reinforcements, with club captain John Terry likely to leave at the end of the season.
And though Koulibaly signed a new contract after Chelsea’s failed pursuit last summer he admitted his future was far from clear this year, telling Talksport: “It would make me happy to come and play here, but I now I have to go to Napoli.
“In the future you never know. Now I concentrate on my club and we will see next season what I have to do.
“I think I will stay in Napoli but you never know. I can't talk about it now. We will see.”
In an exclusive interview with Standard Sport in October Napoli chairman Aurelio De Laurentiis revealed that Conte sufficiently desperate to acquire Koulibaly that he directly intervened in the transfer chase.
“Last summer Conte from Chelsea called me: ‘Aurelio, please, sell me Koulibaly,” De Laurentiis told Standard Sport.
“He was offering and offering and offering. ’Marina [Granovskaia, Chelsea’s lead transfer negotiator] gave to me that amount of money to spend for Koulibaly.’
“I said: ‘My friend I will give him to you if I don’t need him. But I need him. What do you want me to do? I cannot sell you Koulibaly’.”