Chelsea are interested in Leicester City centre-back Wesley Fofana as they weigh up their transfer plans amid contract disputes with Antonio Rudiger and Andreas Christensen.
The 20-year-old is currently out injured after suffering a broken fibula and ankle ligament in a pre-season friendly against Villarreal.
However, the France Under-21 international remains regarded among the best in his age group in world football, including by scouts behind the scenes at Stamford Bridge.
How likely are Chelsea to sign Fofana?
Chelsea won't make a move for Fofana in January but will weigh up a big-money deal ahead next summer as they must wait and see how he recovers from serious injury, with a return slated for the next month or so.
The Foxes will likely set a huge asking price on their prized asset, though, with his contract not due to expire until June 2025.
Chelsea are also still interested in signing Sevilla's Jules Kounde having had a summer approach knocked back by the Andalusian club.
The France international wanted to move to the European champions but they never met his asking price. Now, in January, Sevilla will not entertain any negotiations unless Chelsea force a move by hitting his £68 million ($90m) release clause.
Juventus' Matthijs de Ligt has also been offered to the Blues ahead of a possible summer move, with the Italian giants open to a sale to remove his sizable salary from their wage bill.
The focus on defenders comes with Chelsea having so far failed to renew the contracts of either Rudiger or Christensen.
Real Madrid are leading the race for Rudiger, but the Blues remain more hopeful of keeping Denmark international Christensen at the club for a while longer despite having faced problems in negotiations.
Their deals expire in June 2022, along with the contracts of Cesar Azpilicueta and Thiago Silva. However, the talks around the two more experienced defenders are likely to be easier than with the younger stars who are generating huge interest over a free transfer.
Is there any other transfer activity at Chelsea?
Chelsea are facing injury concerns in midfield and at left wing-back ahead of the January transfer window.
In both areas, the plan is to bring players back from injury rather than dip into the transfer market.
Ben Chilwell has suffered a partial tear to his anterior cruciate ligament and it is hoped that he can return by mid-January at the latest.
Despite attracting loan interest in the winter window from teams in Serie A, Chelsea will block Malang Sarr's exit until they know whether Chilwell faces surgery.
Sarr's few appearances for the Blues have attracted stronger interest in him after only receiving interest from Eintracht Frankfurt, Greuther Furth and Brest last summer.
Manager Thomas Tuchel wants everybody in his squad to stick around and is moving players out of position to cover injury-hit areas. Saul recently played at wing-back with only Marcos Alonso available on the left but Tuchel is also willing to play Callum Hudson-Odoi or Azpilicueta in the role.
Chelsea also have the option to recall Ian Maatsen who has excelled on loan at Coventry City in the Championship.
In a similar vein, should Chelsea's midfield issues continue into January, they may opt to recall Billy Gilmour from his loan spell at Norwich City.
There will also be a recruitment drive for English-based academy players in January after Brexit has curbed big clubs from dipping into the European market to boost their youth squads.