The 20-year-old has impressed during his season-long loan spell at Atletico Madrid and it is understood that the Spanish outfit are ready to offer him a permanent move to the Vicente Calderon.
However, the Blues see the Belgium international as long-term successor to Petr Cech and are reluctant to allow the former Racing Genk star to leave in the next transfer window.
Courtois, who penned a five-year contract with the Stamford Bridge club in July 2011, says he is in constant touch with Chelsea, despite being out on loan.
He told The Times: "I speak to Christophe Lollichon, the goalkeeping coach, maybe once every two or three weeks. Maybe if I was older and the club had tried to sell me but couldn't, they would have sent me out on loan and forgotten about me, told me not to bother them. But that's not true at all. They make sure I know they are interested in how I am doing.
"It is true that, at the moment, I am not sure what is going to happen next year because it is not only me that decides. It was me that decided to go to Chelsea, though, and I am really happy to be a Chelsea player.
"Before the end of the season, we will sit down and talk again. Whatever decision we take I am sure will be the right one. If I can stay here and we are in the Champions League, maybe that is better than being in the Premier League. I do not have experience in the Champions League, and that is the level Chelsea want me to get to."
To find out more about live football on Sky Sports, Click here