Chelsea are eyeing Sporting CP defender Ousmane Diomande for the January market.
Diomande came close to joining Arsenal over the summer, but is now a target for the Blues, says The Sun.
The young centre-half's contract holds a 70m buyout clause.
Chelsea have identified the Ivory Coast international as a potential successor to Thiago Silva. The veteran's deal expires in June.
Also interested in Diomande is Newcastle.
