Chelsea have watched Atletico Madrid's Jose Gimenez as Frank Lampard assesses his options for defensive signings this summer, according to reports.
Lampard could choose to make changes to his central defensive options in the coming window after a spell in which his players in that role have faced significant criticism.
But he would have to sell or loan out at least one of his current centre-backs if he wants to bring in a new player in that position as there are current a number in the squad.
Chelsea's issues at the back were highlighted as they lost 5-3 to Liverpool at Anfield on Wednesday night, which means their place in next season's Champions League is now in doubt.
While, according to the Telegraph, Declan Rice is their top target, West Ham do not want to sell and are in a strong position after staying up mathematically.
They would want £80million for him and would not be keen on the likes of Michy Batshuayi and Ross Barkley in exchange.
While Chelsea would benefit from Rice telling West Ham he wants to move to Stamford Bridge, the Blues are also looking elsewhere.
Gimenez is reported to be one of those options as Chelsea have had scouts at Atletico Madrid's games a number of times.
Lampard has previously said he wants players who are good in the air as he looks to resolve issues in defending set-pieces, and that is an attribute the 25-year-old has.
While he has previously struggled with injuries, he has been a regular this season.
The Uruguayan has a £109m release clause and Chelsea would not meet that – meaning they'd have to negotiate a much lower price.
They are also keen on Jan Oblak, who has a clause of the same value.
Chelsea have also considered re-signing Nathan Ake but the Bournemouth defender's lack of height might count against him.
He would be the cheapest option and could move for less than his £40m buy-back clause if Bournemouth are relegated. Manchester City are also keen.
Chelsea would have to move on one of Antonio Rudiger, Kurt Zouma, Andreas Christensen and Fikayo Tomori for a signing to take place in central defence.
Similarly, at left-back, either Marcos Alonso or Emerson Palmieri would have to leave for them to push forward with their interest in Ben Chilwell.