The 20-year-old joined the Blues in 2011 but has never featured for the club. Instead, he has spent two seasons on loan in La Liga with Atletico Madrid.
Recent speculation had suggested that Courtois may stay with Atletico permanently, perhaps with striker Radamel Falcao moving in the opposite direction.
However, Courtois has denied those reports by insisting that Chelsea are keen for him to remain their player.
"A lot of things the press say are nonsense. They are guessing. They know Chelsea want Falcao but Chelsea have told me, 'The last thing we want to do is sell you'. Maybe they are lying to me but I don't think so," he is quoted as saying by the London Evening Standard.
"It was strange joining Chelsea but when I signed for them I knew I would be loaned out to a team. They had a five-year plan for me.
"I only went to Chelsea to take my medical. I then went straight to Atletico and had a good year so I preferred to stay for another year."
Courtois is believed to have cost the West London outfit £7m.