Belgian goalkeeper has been an ever-present in the Chelsea side since 2013, but is reportedly refusing to extend his time at the club beyond 2019.
Thibaut Courtois yet to sign new Chelsea deal over interest in Real Madrid move - reports
Belgian goalkeeper Thibaut Courtois has delayed signing a new contract with Chelsea to keep open the possibility of joining Real Madrid, according to reports in the Spanish media.
Courtois, 25, has been Chelsea's undisputed No 1 since 2013 following a three-year loan spell with Primera Liga side Atletico Madrid, helping the club win two Premier League titles and the 2015 League Cup. During his time with Atletico, Courtois won the Primera Liga, Copa del Rey and Europa League.
According to Marca, Courtois is now sounding out the possibility of a switch to Atletico's city rivals, Real Madrid, and is the primary reason behind his refusal to extend his time at Chelsea beyond his current contract, which expires in 2019.
Courtois remains settled and happy at Stamford Bridge, thankful towards the club that signed him as a youngster and put faith in him to replace long-time custodian Petr Cech as first-choice goalkeeper.
However, the Belgian is reportedly interested in a move to Real Madrid, aware that the Spanish, European and world champions are in the market for a long-term goalkeeper.
While Madrid are thought to be satisfied with the contribution of current keeper Keylor Navas, their continued pursuit of Manchester United's David de Gea is evidence of their desire to secure an upgrade.
Indeed, De Gea remains a top target for Madrid and their president Florentino Perez, although failure to land Spain's No 1 could see the club turn to Courtois.