Courtois signed for Chelsea in the summer of 2011 from Genk, but the Belgium international has yet to make a first-team appearance for the Premier League club.
He has enjoyed two successful seasons with Atletico after replacing David de Gea and has previously expressed a wish to extend his time at the Vicente Calderon.
Neither Chelsea nor Atletico have confirmed a deal has been struck but the 21-year-old said on Saturday he will be heading back to Spain.
He was quoted by media in Spain and Belgium as saying at a national team press conference in Kortrijk: "I've chosen to stay at Atletico.
"I have to continue playing and at Chelsea there's (Petr) Cech who has always been a great goalkeeper.
"At Atletico I'm sure I can play and I can continue to be the first-choice keeper of the Red Devils (Belgium).
"In the course of the season, we will see if I return to London."
Courtois started for Belgium on Friday night as they beat Serbia 2-1 in a World Cup qualifier in Brussels and claims to have the blessing of incoming Chelsea boss Jose Mourinho to remain in Spain.
"I spoke with Mourinho and he told me the best thing is to continue maturing," he added.
In 2012 Courtois helped the Rojiblancos win the Europa League and UEFA Super Cup, while last season he won the Zamora Trophy as the goalkeeper with the lowest goals-to-game ratio in the Primera Division after conceding 29 goals in 37 appearances.