The Belgian international, who is currently in his third season on loan at Atletico Madrid, is widely regarded as one of the best goalkeepers in world football.
As it stands, the 21-year-old is due to return to his parent club in the summer, but Petr Cech is the current number one at Stamford Bridge.
"Jose Mourinho has said that he waits for him at Chelsea, so we will negotiate his return," Thierry Courtois told Marca.
"It is clear that who is now the number one is Petr Cech, so the coexistence between the two is impossible.
"Alternating between the two would be possible, but it is not what we want. And for now, it's impossible to go to a club where he is the second goalkeeper."
Atletico have reiterated their desire to sign Courtois permanently on a number of occasions.