Kalidou Koulibaly has agreed personal terms with Chelsea ahead of what could be a huge second summer signing for the Blues.
The club finalised their first deal of the window earlier this week as Raheem Sterling signed a five-year deal in west London. Although there's yet to be an official announcement, the Englishman is set to join up with Thomas Tuchel's squad in the US this week.
Meanwhile, Chelsea have been looking to strengthen at centre-back for quite some time. After losing Antonio Rudiger to Real Madrid and Andreas Christensen to Barcelona - both on free transfers - Tuchel needs to add at least two defenders this window.