Chelsea have reportedly not held any fresh talks with Antonio Rudiger over a new contract since August.
The 28-year-old's current deal expires at the end of this season, and he will be allowed to discuss terms with overseas clubs for a free transfer from January 1.
Rudiger remains a key part of Thomas Tuchel's first-choice XI at Stamford Bridge and is understood to be open to staying at the club if they are able to meet his wage demands.
However, The Athletic reports that Chelsea have not returned with another offer since Rudiger rejected a £140,000-a-week deal during the summer.
The Germany international is understood to be holding out for closer to £200,000 a week, although recent reports have suggested that he could become one of the world's best-paid defenders if he leaves Chelsea on a free transfer.
Real Madrid are understood to be leading the race for his signature, while a host of other top European clubs - including Manchester City, Liverpool, Bayern Munich, Juventus and Paris Saint-Germain - are also thought to hold an interest.
Rudiger is currently on around £90,000 a week at Chelsea - significantly less than a number of his teammates, including compatriots Timo Werner and Kai Havertz.
