The transfer of Nicolás Fonseca from León to Valencia fell through because the Mestalla club was unable to officially finalize the verbal agreement, primarily due to financial fair play restrictions. Valencia had asked for a ten-day extension to complete the deal as their focus was on signing a forward after Umar Sadiq and Rafa Mir left the club. However, León declined the request for an extension, effectively ending the negotiations. Initially, León was open to the idea of Fonseca's departure, with hopes of recouping more than the 2.1 million euros they had spent on him in January. Talks had been advancing positively, and Fonseca was excluded from the squad against Cruz Azul, but now he has to reintegrate with the team for the upcoming Leagues Cup and Apertura 2025. Journalist Paco Montes reported that the collapse of the negotiations was a result of Valencia's financial limitations. León had been willing to negotiate after Valencia expressed interest in Fonseca over a month ago, especially after Enzo Barrenchea's confirmed move to Benfica. Despite the promising start, León ultimately chose not to prolong the negotiation period, particularly as Valencia needed to address their squad requirements for the forthcoming La Liga 2025-26 season.