Diego Simeone sat on the set at a television studio, a huge mocked-up bag of cash on the desk in front of him representing the €38m (£31.5m) in Diego Costa's buy-out clause. Simeone is a pragmatist, a man who has talked often of Atlético Madrid's limited resources, and he had just admitted with a heavy heart that if a club met the striker's valuation he would have no choice but let him go, just as he had with Radamel Falcao the previous summer.

There is no money for big signings. He would find an alternative, a cheaper one. Now, Simeone was asked, would you use this big bag of money to sign Thibaut Courtois permanently? Atlético Madrid? €38m? On a goalkeeper? Were they mad? Simeone did not hesitate. "Without doubt," he said. Better still, Simeone may get Courtois for free. For one more year at least. The question has been repeated often, not least by Courtois himself: where next?

After Atlético Madrid's 1-1 draw at Camp Nou on Tuesday night the Belgian said he hoped to be able to announce what his future will be "next week". He had already said that his immediate future would be either Chelsea or Atlético, no one else. The long-term plan was less clear, but that too is falling into place. When Courtois joined Chelsea he signed a five-year deal. Although he was loaned to Atlético, Chelsea kept a close eye on him, involved in his training regime, maintaining contact and occasionally bringing him back to London.

Courtois grew in Madrid and he was happy too. Chelsea wanted him to go on loan to an English club – the game there is different, after all. But Courtois insisted on staying. He has been a massive success: winner of the Europa League and the Copa del Rey, a contender for La Liga and the European Cup this season. "[Chelsea's goalkeeping coach] Christophe Lollichon watched me a lot, so he saw that it's a good league and that I am playing well," Courtois told the Guardian.

"They would rather have a happy goalkeeper playing in a good team in Spain than playing for a team fighting relegation in England. OK, I would adapt to football in England if I went there on loan but you will let in two or four goals and that is not good for your confidence. For that reason I think it was easy for them to say: 'Yeah, you can stay there.'"

But this is his third season at Atlético. The distance grows and so does Courtois; he does not truly feel like a Chelsea player. The uncertainty has become a problem and so has impatience, the sense that the club who own him may have doubts about him: he is only 21 but he expected to be at Chelsea by now. Playing, too. He is certainly good enough, but so is Petr Cech.

After last season's Copa del Rey final, in which Courtois had made a miraculous save to help Atlético defeat Real at the Bernabéu, the full-back Filipe Luis walked past Courtois in the mixed zone shouting: "What a save, madre mia, what a save! The best goalkeeper in the world!"

Jimmy Floyd Hasselbaink agreed on Tuesday night, arguing on Sky that only Manuel Neuer is as good. Hasselbaink said that he thinks the Belgian should return to Stamford Bridge and be the No1 next season. José Mourinho, the manager defeated by Courtois's saves in that final, said rather pointedly that whatever happens depended entirely on Chelsea but there was something in the tone that did little to comfort the keeper.

And as the end of his contract draws nearer, so the possibilities seemed, at least momentarily, to widen. Certainly, interest from elsewhere has strengthened Courtois's hand while the frustration of not knowing strengthened his resolve. Would Chelsea let him go? Could Courtois look to break free? Do they see in him a potential profit? Could he see out his Chelsea contract and then leave? Would he lay down an ultimatum, a road map to follow? Could he?

It is hard to believe Chelsea would let a talent this big go but their continued faith in Cech has slowed his progression. Another possibility has arisen – Courtois as a bargaining chip in other signings. Diego Costa, for example. There had been reports about a move to Real Madrid, suspiciously timed to coincide with the two capital teams' meeting in the league and cup, and Barcelona's manager, Gerardo Martino, was asked on Tuesday night if there was a chance of the Catalan club moving for him. "I'm can't talk about things that could be two years away," he said.

Barcelona have implied that they doubt Courtois's ability with his feet; a key skill at the Camp Nou, where the keeper is another player. Chelsea are also conscious that a sale, as with Kevin De Bruyne and perhaps in the future with Romelu Lukaku, could represent good business. Atlético still believe Courtois will sign a new deal at Chelsea and be allowed to spend another season in Spain. That is their hope. The timings have played into their hands: Cech's longevity has given them one of the best goalkeepers there is, a loan player who has been at the club longer than many permanent signings.

At the end of this season, Courtois will have been an Atlético player for three years. They are hopeful that he will play at the Calderón for a fourth. The draw at the Camp Nou underlined how significant he is. He made three impressive saves from Sergio Busquets, Andrés Iniesta and Lionel Messi. "He's one of the best goalkeepers in the world, there's no doubt about that," Martino said.

Atlético are hopeful that they can enjoy him for another season. After that, Chelsea could enjoy him for a decade or more.