With Antonio Rudiger and Andreas Christensen no longer at the club, Chelsea are in desperate need of centre-halves.
Jules Kounde and Matthijs De Ligt have had their names thrown out there, but now Napoli's Kalidou Koulibaly has been added to a shortlist full of potential suitors.
The 31-year-old's agent was reportedly in London recently. Due to the high prices of Kounde and De Ligt, the Blues are enquiring about the possibility of bringing him in.
Koulibaly has made 317 appearances for Napoli since joining in 2014, however, his contract is out next summer, meaning there is potential for a deal to take place.
The focus at Stamford Bridge will be on finalising the Raphinha deal before then shifting the attention back to a defender (particularly a centre-back).
It is Todd Boehly's first summer as owner of Chelsea, and it looks set to be a big one to help Thomas Tuchel get back on track to success in the upcoming campaign.
It would show real intent by bringing in a dominant figure like Koulibaly, who would perfectly fit in the centre of the back-three. The only real weakness to his game is his pace, but that shouldn't be too much of an issue.