Carlo Ancelotti Says Kalidou Koulibaly Is 'Not for Sale' Despite Upcoming €150m Release Clause

​Carlo Ancelotti has insisted that Kalidou Koulibaly is the best centre back in the world and claimed that the Napoli superstar is worth €150m.

The Senegal international has established a strong reputation as one of the most commanding defenders on the continent since arriving to Naples from Genk in 2014, and has been the subject of regular transfer speculation in recent years.

​Manchester United have been among the clubs most consistently linked with Koulibaly, but Ancelotti has sought to warn any potential suitors against a move for his prized asset. As quoted by ​AS, the ​Napoli boss told Tuttosport: "The best centre back in the world? I would say so.

"And he can still improve. He is worth €150m and he is not available for transfer. Koulibaly's contract expires in 2023, in 2021 there's a €150m clause but Napoli do not need to sell, the president [Aurelio De Laurentiis] does not want to sell and the question doesn't come up."

Manchester United's search for a top-class centre back proved problematic towards the end of Jose Mourinho's ill-fated spell as manager of the Red Devils and rumbles on as an issue under current boss Ole Gunnar Solskjaer.

Having missed out on Champions League qualification for next season, United are expected to invest heavily in revamping their squad this summer, with ​Leicester's Harry Maguire and Ajax sensation Matthijs de Ligt also said to be targets for Solskjaer at centre back.

Meanwhile, Napoli have fallen well short of their previous campaign in which they pushed champions ​Juventus close for the Serie A title, with the Partenopei 17 points adrift of the Bianconeri this season in second.

"Second place is not a discredit to us, it's a credit to Juventus, who are going along at an exceptional pace," Ancelotti added. "If they [Juve] continue like this, they can finish with 100 points."