Thibaut Courtois
Courtois received a phone call from Mourinho this month clarifying his future, reports suggest. GettyImages

Jose Mourinho has informed Thibaut Courtois he will replace Petr Cech as his number one in goal at Chelsea next season, according to reports in Spain.

Courtois and Atletico Madrid celebrated a magnificent La Liga triumph on Saturday after a draw away to Barcelona was enough to see them clinch the Spanish title for the first time in 18 years.

The Belgian's immediate focus will now shift to the Champions League final against Real Madrid on Saturday but speculation as to his long-term future remains rampant, with a latest twist suggesting he will return to Stamford Bridge as the club's undisputed no.1 choice.

Courtois is reluctant to return to Chelsea, whom he joined for £5m from Genk in 2011, to warm the substitutes' bench having spent the last three seasons starring for Atletico where his reputation as one of Europe's best goalkeepers has grown exponentially.

While Diego Simeone is keen to secure the 22-year-old's services for a fourth season, Spanish radio station Cope suggest Mourinho telephoned Courtois prior to his side's 2-0 loss to Levante earlier this month to inform him that he will return to west London as his first choice.

Such developments will raise questions over the future of Cech, who underwent shoulder surgery this month after suffering a dislocation in his side's Champions League semi-final loss to Atletico.

The Czech international has been an immovable object in the Blues' starting XI following his arrival in 2004 and celebrated another Golden Glove award in the 2013/14 season, sharing the honour with Arsenal's Wojciech Szczesny.

Courtois himself has informed Chelsea on several occasions that he will not settle for a peripheral role should he return to the club, but told reporters after Atletico's league triumph he is still waiting to learn of his parent club's plans.

"If I move somewhere, I will play. With my age, what I want, the most important thing for me, is to play," Courtois said, the Guardian report. "We will see what happens. But Petr [Cech] is one of the best goalkeepers in the world, he won the golden glove in the Premier League, and I have a lot of respect for him, so we will see what Chelsea decide and what they plan to do. You guys will see the decision [then]."