Thibaut Courtois
Courtois has stared for Atletico in two-and-a-half years on loan.

Chelsea are keen to sell Thibaut Courtois to Real Madrid or Atletico Madrid for £25m in the summer, according to one of the most important Spanish newspapers.

There have been plenty of rumours recently about Courtois' future after the prestigious radio station Cadena Ser reported earlier this week that the keeper had agreed terms in principle to join Real Madrid in 2016, once his contract at Stamford Bridge expires.

Even though, in that case, Real Madrid would secure his transfer for free, the Spanish giants would rather have Courtois this summer and according to AS Jose Mourinho would part with the young keeper if Los Blancos meet his £25m valuation - and give Chelsea a £20m profit on their initial investment.

AS claims that Mourinho would sanction that deal as he needs to sell some of his squad to fund reinforcements. The reports claim that Chelsea currently have money to sign a striker, Mourinho's main target, but they would need to recoup some more if they want to strengthen other positions.

Atletico Madrid's president revealed last month that Chelsea valued Courtois at £20m, but according to AS he is likely to fetch £25m this summer.

The Spanish newspaper suggests that Mourinho would rather sell him at the end of the season, as in 2015 Courtois will have just one season remaining on his contract and his price will be lower.

Atletico Madrid are set to fight their city rivals to secure the Chelsea loanee on permanent basis. However their precarious financial position would not allow them to meet Chelsea's demands, and AS claims they are considering offering Diego Costa in exchange to get the deal done.

Courtois, 21, is currently enjoying his third season at the Vicente Calderon Stadium where he has built a reputation as one of the finest shot stoppers in Europe.

Mourinho wants him back at Stamford Bridge to fight for the number one position with Petr Cech but the Belgium international has said many times that he will just return to West London for a guaranteed starting place.

Courtois has denied any agreement with Real Madrid or any other club, saying: "It's completely false.

"Everyone knows I've got a contract with Chelsea and I'm happy at Atlético".