Chelsea are understood to have made a renewed bid for Kalidou Koulibaly, the Napoli defender, after their advances were first rebuffed almost a year ago.

Senegal international Koulibaly, who joined the Serie A club from Belgian side Genk in 2014, is the subject of a £53 million bid from the Premier League champions, according to a report from Tuttomercatoweb, who added that Napoli are ready to play hardball.

However, Koulibaly's agent reportedly told Mondo Napoli that his player 'might' be moving this summer while adding that Antonio Conte's team were a 'world-class' outfit.

"Koulibaly? The transfer market is long as it will be open until August 31, something might happen before then," the agent said.

"Chelsea? They are a world-class team that many players would like to join but I don't want to talk about this now."