The Belgium international only departed Stamford Bridge as recently as 2019, Los Blancos agreeing to a deal worth in the region of £130m if all add-ons are fulfilled.
However, the 30-year-old has struggled with injuries and for form during his stint at the Bernabeu, circumstances which makes a contract extension past 2024 increasingly unlikely.
Earlier this month, it was claimed that Chelsea held an interest in securing a reunion with the former star man, providing that they can negotiate a deal with Real.
According to El Nacional, the European champions have informed the Spanish giants that they are prepared to pay £42m for the playmaker.
While Florentino Perez has demanded that Chelsea pay a slightly bigger fee, the report hints that a deal has a realistic chance of going through next summer. body check tags ::