Chelsea are facing the possibility of four first-team defenders leaving the club for free next summer, the UK Mirror reports.
It is understood that Barcelona are monitoring the situation and are ready to pounce.
Antonio Rudiger, Andreas Christensen, Cesar Azpilicueta and Thiago Silva are all out of contract in June 2022.
As it stands, none of them is close to signing new contracts at Stamford Bridge.
Rudiger has made over 150 appearances for Chelsea since arriving in a £29 million deal from Roma and has become a fans’ favourite due to his no-nonsense style of play.
But the German appears to be edging closer to the exit with Real Madrid, Bayern Munich and Paris Saint-Germain all keen.
Christensen was dropped earlier this month, after twice refusing to sign a contract extension despite reaching a verbal agreement with the club.
The 25-year-old has been at the club since 2012 and has become an important part of the club’s setup under Thomas Tuchel’s reign.
Captain Azpilicueta has been linked with a return to his native Spain, with Barcelona thought to be pushing for a move.
Silva is however the most likely to remain at the club, as he is close to agreeing fresh terms.