Napoli chief Aurelio De Laurentiis has admitted that the club will inevitably have to sanction the sale of Kalidou Koulibaly one day.
The Senegal international has emerged as one of world football's best defenders since moving to Naples in 2014, making 212 appearances in all competitions for the Serie A club.
Manchester United expressed serious interest in signing Koulibaly in 2017 and 2018, but Napoli refused to budge on their £105m valuation.
Speaking on the subject of Koulibaly, De Laurentiis told Sky Sports Italia: "I loved Koulibaly the man so I refused €105m, but a time will come when I'll have to sell him. Whoever says we didn't improve our defence is wrong."
The Red Devils have since broken the world transfer record for a defender by signing Harry Maguire from Leicester City for £80m over the summer.
It has been claimed that Napoli view Samuel Umtiti as an ideal replacement for Koulibaly, with the former reportedly deemed surplus to requirements at Barcelona.
