Chelsea are willing to pay €40 million for Napoli defender Kalidou Koulibaly according to the La Gazzetta dello Sport.
Per the source, the Blues are looking to strengthen their back line after leaking in 53 goals in 38 Premier League games last season.
Head coach Antonio Conte is looking to reinforce the defence with Serie A defenders he is all too familiar with.
Chelsea owner Roman Abramovic would reportedly be willing to spend as much as €40 million for the powerful defender.
Napoli could end up losing their second key player over the summer following the departure of Gonzalo Higuain who was snapped up by Serie A rivals Juventus.
Koulibaly joined Napoli from Belgium outfit Genk back in 2014 and has made a total of 81 appearances in all competitions since making his move.
The 25-year-old Senegalese defender has not been sent off once since joining the Serie A outfit.