Chelsea remain locked in talks with Sevilla for Jules Kounde.
Chelsea want to include defender Kurt Zouma in the deal - who was in talks over a move to London rivals West Ham - but there's currently no agreement over the defender's value.
But should Sevilla sanction a move, the Spanish side will move for Schalke's Ozan Kabak, who spent the second half of last season on loan at Liverpool.
Italian transfer expert Fabrizio Romano said on Twitter: "Sevilla are still looking for a new centre back as Jules Koundé talks with Chelsea continue.
"There's still no agreement on Kurt Zouma value.
"Sevilla have offered €10m to sign Ozan Kabak. Schalke turned down the opening proposal - price tag around €15m. Talks on."