The on-loan goalkeeper has made nine full appearances for Atletico in Europe, including their quarter-final second-leg win over Barcelona on Wednesday that booked Diego Simeone's men a final-four spot.
Atletico president Enrique Cerezo said if the La Liga club were to draw Jose Mourinho's men in the semis, Courtois would not be in goal.
There is one avenue Atletico could use to deploy Courtois, but it involves paying Chelsea upwards of £8million.
"If we draw Chelsea, Courtois won't play. It is a figure we cannot pay," Cerezo told Onda Cero.
Courtois, 21, has expressed his desire to return to Chelsea and take the number one spot from incumbent Petr Cech.
The Belgian has two years remaining on his contract with the Londoners, but may yet help Atletico to the La Liga title first - with the capital club top of the table by a point to Barcelona.
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