Uefa will come under pressure to investigate the Thibaut Courtois loan agreement between Chelsea and Atletico Madrid if they are drawn together in the Champions League, reports the Daily Mail.
The semi-final draw for the Champions League takes place on Friday morning and could potentially see The Spanish club paired with Chelsea.
That would mean that on-loan Chelsea goalkeeper Courtois could face his parent club in what would be a high stakes match for both clubs.
However, it was revealed on Wednesday that a clause in the loan agreement would see Atletico have to pay up to £5 million to allow Courtois to play; a fee they have already confirmed they can not afford.
If the two clubs are drawn together, it is believed that Atletico will appeal to Uefa to run the rule over the contract agreement between the two clubs to see if Chelsea acted within the spirit of the competition or not.
Courtois has been one of Atletico's best players since joining them on loan three seasons ago. Not only has he helped them to the final four of Europe's elite competition but also the top of the La Liga table.
If he is unable to play, it would be a huge blow to Diego Simeone as well as the player himself, who has reportedly asked Chelsea to waive to appearance fee for his sake.
If no agreement can be found, reserve goalkeeper Dani Aranzubia is likely to come in. The 34-year-old is out of match practice, having only featured in two games for Atletico this season.
Uefa have since confirmed that they will not allow such a clause to be enforced by Chelsea, freeing Courtois to play in any potential match between the two teams.
A statement of Uefa's official website read: "Any attempt to enforce such a provision would be a clear violation of both the UEFA Champions League and the UEFA Disciplinary Regulations and would therefore be sanctioned accordingly."