By Harvey Byrne

Chelsea are preparing a bid of between £43.4million and £47.7million for Napoli defender Kalidou Koulibaly, according to a report.

Koulibaly’s agent told the Sun last month that Everton, Chelsea and Juventus were all interested in the 25-year-old defender.

Italian news outlet Calciomercato have now claimed that that the Stamford Bridge club are planning to make a huge bid of up to £47.7million for the centre-back within hours.

It is claimed that Napoli chairman Aurelio De Laurentiis could tempt the 25-year-old to stay for another year in Naples, with the promise of a transfer next summer.

However, Koulibaly’s contract expires in 2019 and the Senegal international has already rejected a recent offer of a new deal.

The centre-back would become the most expensive player in Everton’s history if the Toffees were to match Chelsea’s offer and he chose to join the Goodison Park club, surpassing the club’s £28million record signing Romelu Lukaku.

Koulibaly has been at Napoli for two years since joining from Metz for £6.5million, and has now played 60 times in Serie A.

The defender played 33 times in the Italian top flight in the 2015-16 season as Napoli finished nine points behind Juventus in second.

Ronald Koeman has been active in his search for players since arriving at Goodison Park this summer, and has specifically targeted a centre-back after John Stones left for Manchester City in a £47.5million deal this summer

The club have been linked with Sunderland’s Lamine Kone and Jose Fonte from Southampton, after also bringing in Ashley Williams from Swansea.

In other Everton transfer news, Charlie Austin has dropped a clear hint that he will not be leaving Southampton this summer.