Lukaku, 21, has spent the last year out on loan at Everton, and whilst he impressed during his spell on Merseyside, the expectation is that the Belgian will be sold this summer, with a number of clubs lining up moves to sign the former Anderlecht man.
He wasn't even the only young Belgian who impressed out on loan, as goalkeeper Courtois starred for Atletico Madrid once again in his third season with the Spanish club. He has now made over 150 appearances for Diego Simeone's side, and was a key part of the team that won the La Liga title for the first time in almost 20 years.
Yet whilst Simeone would love to keep the 22-year-old in the Spanish capital, Chelsea ultimately hold all the power in deciding Courtois' future - and that's a decision that manager Jose Mourinho is still yet to make, with Courtois currently at the World Cup with Belgium.
Speculation has suggested that Mourinho will look to field offers for long-term shot stopper Petr Cech in order to make Courtois his definitive first choice goalkeeper, and team mate Lukaku says that whilst he doesn't know what Courtois' future will hold, he thinks it's time for Courtois to be given a shot in the Premier League.
"I don't know, I only read about it. You'll have to ask him. I think it's time. He's played at a very high level in Spain for three years. It's time to see him in England," said the striker.
Depending on how far Belgium can get in the World Cup, there may still be no decision over Chelsea's goalkeeping situation for some time. Yet both Cech and Courtois will want to play regular first team football, so keeping both appears illogical at this point - and the calls for Courtois to be handed the number one jersey continue to get louder and louder.