Romelu Lukaku's departure means a new forward is essential, but for Chelsea the most pressing area of concern this summer comes in defence.
With Antonio Rudiger and Andreas Christensen gone - the former leaving a gaping hole after starting 34 league matches last season - Thomas Tuchel knows strengthening defensively is his biggest priority in the coming months if they are to seriously compete for the title next season.
The Blues have a number of centre-backs in their sights, including Juventus' Matthijs de Ligt, Sevilla's Jules Kounde and Napoli's Kalidou Koulibaly.