While Chelsea boss Thomas Tuchel has been active in the market of late, he is known to be keen to bring at least three more additions.
The Blues have their eyes on someone who currently features in the German top flight.
However, the report adds that the Bundesliga outfit may be prepared to demand somewhere in the region of £60m for the 23-year-old defender.
As it stands, it is suggested that the West Londoners have not progressed past making an enquiry about the Burkina Faso international’s availability.
The centre-back has made 63 starts and seven substitute appearances in the Bundesliga since joining Leverkusen in January 2020.