Player once signed with Real Madrid and Barça at same time

In 1953, Barcelona signed Alfredo Di Stéfano after reaching an agreement with River Plate, the club that owned the rights to the player. Simultaneously, Real Madrid carried out negotiations with Millonarios, the team that Stéfano was playing for then. The Spanish Football Federation said Stéfano should play alternate seasons with each club, however, Barça rejected the verdict and released Stéfano.