Chelsea defender Antonio Rudiger has commenced pre-contractual discussions with Real Madrid, Bayern, PSG and Juventus about a summer switch, reports claim.
The German centre-back's current deal at Stamford Bridge expires in six months time - meaning he is free to discuss a free transfer with other European clubs - with Chelsea so far failing in attempts to agree fresh terms.
Rudiger has remained coy on his future but has been heavily linked with a move to Madrid, with reports their player are convinced he will join and become reunited with former Chelsea team-mates Thibaut Courtois and Eden Hazard.
And he has wasted no time exploring the considerable interest in his signature, according to Sky Sports - who believe that the four top sides have all opened talks with him about a possible bosman transfer.
Chelsea haven't given up hope of convincing the player to sign a new contract, the report goes on, saying Rudiger's camp have also not ruled out committing his future to the west London club.
But they have so far been unable to come to an understanding on his salary, with Chelsea's £140,000-a-week insufficient. Madrid are believed to be willing to double that amount.
Rudiger and his team turned it down because it meant he would only earn half as much as the club's top earner, Sky's report claims.
Chelsea are facing something of a defensive crisis as Andreas Christensen and captain Cesar Azpilicueta are three more players whose deals expire in the summer, meaning the club could soon experience a exodus at the back.
Thiago Silva's contract had been running down too but gave Chelsea a boost by signing a one-year extension.
Rudiger is said to be committed to giving his all for Chelsea for the remainder of the season, having produced a dramatic upturn in fortunes since his boss Thomas Tuchel replaced Frank Lampard last season.
Under Lampard, Rudiger was frozen out of the side and came close to leaving the club - but quickly became a key part of Tuchel's side after the club legend's sacking and went on to win the Champions League in the summer.
He has played 166 times for the Blues since joining from Roma in 2017, also winning the FA Cup and Europa League during his time at the club.