Chelsea are preparing to make a move for Napoli defender Koulibaly in £60 million deal.
The move signifies a dramatic step forward as Antonio Conte looks to strengthen his defence.
The move for Koulibaly would eclipse the the £47.5 million transfer of John Stones to Manchester City and is also significantly higher than the club's previous transfer record when the Stamford Bridge club paid Liverpool £50 million for Fernando Torres. But it has become clear the the Senegalese defender is the man Conte wants as part of his rebuild at the West London club.
Chelsea manager Antonio Conte
Chelsea have been chasing Koulibaly all summer and will be looking to tie up the transfer with plenty of time to spare before the transfer window closes. But as reported in The Telegraph, Napoli want Koulibaly to remain at the club and have attempted to offer him a new contract but it is understood that the player is keen to move.
But with Chelsea's new bid being seriously larger than any other amount previously mentioned, the question is whether Napoli will have the resolve to resist the move for Koulibaly, havng already sold Gonzalo Higuain to Juventus for £75 million this summer.
There was a belief that Chelsea were willing to pay up to £45 million for the defender, but The London Evening Standard reported that the Blues are willing to pay up to £60 million due to the size of Koulibaly's release clause Napoli owner Aurelio De Laurentis is trying to put in to the defenders contract extension that has been offered.
Both players had indifferent form last season, and with the emergence of Kurt Zouma before his long-term injury, Roman Abramovich's Chelsea may now see their first-choice centre back partnership being Zouma and Koulibaly.
West Ham United's Andy Carroll in action with Chelsea's John Terry and Gary Cahill
There is also the option that Conte could move to a back three, something which he has favoured in the past with Juventus and Italy. The feeling is that at present Chelsea do not have the defenders to set out with a back three, but the signing of Koulibaly would enable them to carry out the system effectively.
At present Conte has limited centre back options at his disposal, with Zouma not expected back until the end of the year at the earliest, but the move for the Napoli centre back is not his only priority. There are rumours circulating that as well as a move for Koulibaly, Conte will also make steps in his move for Everton's former Chelsea forward Romelu Lukaku.
Everton's Romelu Lukaku
The Express has reported Lukaku is still on their radar, and after completing the transfers earlier in the summer of N'Golo Kante from Leicester City and striker Michy Batshuayi from Olympique Marseille, Conte is now moving forward with adding the final pieces to his Premier League squad. But like Koulibaly, any move for Lukaku is likely to need a bid of around £60 million, and even then, there are no guarantees that will be enough for Everton to sell a player back to Chelsea that they bought for £28 million in 2014.