Chelsea are involved in a defender pursuit this summer that looks to be changing direction slightly.
Thomas Tuchel needs to replace both Antonio Rudiger and Andreas Christensen this summer and at the time of writing, not one of them has been replaced yet. There is talk of Nathan Ake arriving back at Stamford Bridge this summer, but they will need to sign another centre-back at least.
Sources: Plenty of names mentioned here and other options in attack for Chelsea this window.
Matthijs De Ligt appears to be a priority target, however, Bayern Munich are also pushing for him and his asking price might be too high anyway.
It looks like Chelsea are making backup plans and moving on those plans, having met with the agent of Napoli defender Kalidou Koulibaly over the weekend, according to Sky Sports Italy, as cited by Football Italia.
In the same report, it also claims the Sport Italia are saying that Koulibaly will not go to Juventus to replace De Ligt if he leaves, which is what has been reported recently.

If true it is a good idea for Chelseafc for a committed player like kouli.