Antonio Conte attempted to sign the 25-year-old last summer but Napoli were reluctant to part with their star man.
Chelsea reportedly had a £58million bid rejected last year but Conte is keen to bring him to Stamford Bridge this summer.
The Italian boss has drawn up a shortlist of transfer targets that includes Koulibaly, who he sees as John Terry's long-term replacement.
Kalidou Koulibaly is under contract with Napoli until 2021
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But Napoli are unlikely to consider any offers less than £60m with the Italian outfit keen to keep hold of him.
However, Koulibaly's agent's latest comments will be of interest to Chelsea with the defender not guaranteed to be at Napoli next season.
“The player is very relaxed, I saw him after the game [against Real Madrid]," Bruno Satin said.
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Kalidou Koulibaly is attracting interest from Chelsea
Antonio Conte believes Kalidou Koulibaly is an ideal long-term replacement for John Terry
“At the moment, we don’t want to talk about his future but with a president like this who has a lot to say, it is difficult for us to affirm 100 per cent that he will be staying at Napoli next season.
“[But] he wants to finish the season on a high even if it will be almost impossible to surpass Juventus for the league title.”
Koulibaly is under contract with Napoli until 2021.