The Chelsea FC shot stopper is facing an uncertain future at the west London side given the Belgium international has 12 months remaining on his current deal.
The Blues goalkeeper has been regularly linked with a move to Real Madrid over the past few seasons as a potential replacement for Keylor Navas.
Chelsea FC sent Courtois out on loan for three seasons at Atletico Madrid where he won the La Liga title and reached the Champions League final.
Courtois’ former girlfriend and two children are still in Madrid to provide one reason why the Belgian goalkeeper would like to return to Madrid.
The Blues have been linked with a swoop to sign AS Roma goalkeeper Alisson Becker and Leicester City number one Kasper Schmeichel in the summer.
Sunday Times reporter Castles believes Courtois is looking to leave the west London side in the summer transfer window.
“Courtois is a disgruntled player trying to get out,” Castles told the Transfer Window podcast.
“He wants to leave, He wants to leave this summer. He is not going to sign a new deal.
“He has made it clear to Chelsea that he will leave next year. Chelsea have a dilemma.”
Chelsea FC finished in fifth place in the Premier League table to miss out on a Champions League spot.
The Blues were 1-0 winners against Manchester United in the FA Cup final at Wembley following Eden Hazard’s winner from the penalty spot.
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