Chelsea manager Jose Mourinho says Asmir Begovic could feature on a regular basis if he keeps back-to-back clean sheets.
The Bosnia and Herzegovina national moved to Stamford Bridge for an undisclosed fee, reported to be in the region of £8m.
He replaces Petr Cech who left the club to join Arsenal.
"It's a big challenge for Begovic because he has Courtois, an amazing goalkeeper who immediately made a great impact when he arrived in England," Mourinho told the club's official website.
"But I wanted to replace Petr not with a good goalkeeper but with a very good goalkeeper.
"I think we have in our squad two of the best five goalkeepers in the Premier League.
"Begovic is going to compete with Courtois. The one with more clean sheets is the one that has to play, but I am so happy and so calm because we have two fantastic goalkeepers."