The 21-year-old has revealed that he was offered by Blues manager Jose Mourinho a return from Atletico Madrid this season, but the keeper opted to remain on loan in La Liga in a bid to secure a place in the Belgium team for next year's World Cup.
"I could have gone [back to Chelsea] and it may have worked out perfectly, but then again I may not have been playing and could have risked losing my starting place with the national team," the London Evening Standard quotes Courtois as saying.
"It would have been a risk for the World Cup. Next year? I can afford to take more risks, but for now, the important thing for me as a young player is to reach a higher level."
Courtois signed for Chelsea from Genk in 2011 for a reported £7m.