Romelu Lukaku - The striker, 28, has proved to be Chelsea's second costliest mistake behind Belgian teammate Kevin de Bruyne. Lukaku's 24 Serie A strikes just helped Inter Milan win a first scudetto in 11 years but the club's financial woes - they are reported to have missed payments due to Manchester United for Lukaku's 2019 transfer - could force the Italian champions to cash in for a fee of around €80 million. Reuters

Thomas Tuchel's wishlist: 5 players Champions League winners Chelsea could target