The Belgian goalkeeper is currently on loan at Atletico from Chelsea, who had hoped that the shot-stopper would be made ineligible for the two-legged European affair.
Chelsea also reportedly attempted to acquire a monetary sum from Atletico in order to allow Courtois to play, but that was rejected by UEFA.
"I have no doubt that he will play against Chelsea. He has no doubts either," Simeone told Onda Cero.
"It's not a concern. He doesn't know where he'll play next year."
Courtois, 21, is widely regarded as one of the best goalkeepers in European football.