The Senegalese centre-back has emerged as a target for both clubs over the course of the past few weeks, with his agent having talked up interest from the Premier League duo while claiming that his client is ready to “leave” Naples.
Everton are understood to have matched Chelsea’s bid for the 25-year-old and offered him a more lucrative deal to pick Merseyside as his next home, but reports claim that the player himself favours west London, with the Blues having put a €45m (£38.2m) proposal on the table for his signature.
The 6ft. 5” defender starred for Napoli as they finished as runners-up to Juventus in Serie A last season and has been lauded for his mix of physicality defensive discipline.
The Italian side are seemingly preparing for Koulibaly’s exit, with Benfica’s Victor Lindelof a target.