Chelsea boss Thomas Tuchel is targeting four new defensive signings.
The Evening Standard says Tuchel has told Chelsea he wants to sign three central defenders and one wing-back this summer.
The Blues boss has been planning a defensive overhaul following the departures of Antonio Rudiger and Andreas Christensen.
Marcos Alonso and Cesar Azpilicueta are expected to join Christensen in departing Stamford Bridge for Barcelona, leaving the Londoners short of numbers at the back.
Centre-back Kalidou Koulibaly has already arrived from Napoli in a £33m deal, but Tuchel is not yet satisfied.
Chelsea are keen on Paris Saint-Germain’s Presnel Kimpembe, and are set to revive their interest in Sevilla’s Jules Kounde.
Meanwhile, Lens’ Jonathan Clauss has been linked with a move to the Premier League club.