Atletico Madrid keeper Thibaut Courtois will not face his parent club Chelsea if the two sides are drawn against each other in the last four of the Champions League.
Atletico reached the semi-finals of Europe's premier competition for the first time in 40 years after a 2-1 aggregate victory over Barcelona on Wednesday night.
Their president, Enrique Cerezo, confirmed afterwards that Courtois' contract includes a clause that would force Atletico to pay the Blues a reported £8.25 million fee in order for him to play against them.
As reported by Liam Twomey of Goal.com, Cerezo said: "If we draw Chelsea, Courtois won't play. It is a figure we cannot pay."
This will be something of a blow to the Madrid outfit if the two sides are drawn together as the Belgian shot-stopper has been a key component for Atletico, whose defensive record is the best in the Champions League this season.
They have conceded only five goals in 10 matches in the competition and the 21-year-old has four clean sheets from nine appearances this season, per Squawka.com.
He made a vital stop to deny Neymar during the second half of Wednesday's encounter, and football writer Graham Ruthven believes Courtois to be one of the best keepers in the business:
Courtois joined Chelsea from Racing Genk in 2011 and was immediately loaned out to Atletico. He currently has two years left on his contract with Jose Mourinho's side.
The likely replacement for Atletico at the back would be Spaniard Daniel Aranzubia, who has one appearance in Europe this season and also only a single La Liga appearance—a 2-0 loss to Almeria in which he was sent off.
Other possible semi-final opponents for Atletico are fierce city rivals Real Madrid or defending champions Bayern Munich.
While Diego Simeone's side do currently sit three points clear of Real at the top of the La Liga table, they will likely not want to draw Real, who have been terrific in the main in this season's Champions League.
Bayern Munich would also constitute a very tough draw. While Chelsea did fantastically well to come through against PSG in the last eight, they are the weakest side left in the competition.
Thus, if Atletico have designs on reaching the Champions League final in Lisbon in May, the ideal draw for them would be the West London side.
However, without Courtois they would be greatly weakened, meaning that Friday's draw will cause distress for Atletico no matter what the outcome.