Real Madrid president Florentino Pérez has refused to confirm that David de Gea will be the replacement for outgoing goalkeeper Iker Casillas. Pérez was asked about his plans for replacing Casillas, who has left the club after 25 years for Porto, at Monday's hastily-arranged press conference. He mentioned the Manchester United goalkeeper by name but refused to add detail owing to the club's "friendly" relationship with the Premier League giants. "It will be impossible to substitute him and our only thoughts are about saying goodbye to Iker at the moment," said the club president in response to a question over whether the 34-year-old left the Bernabeu in light of the probable competition from the former Atletico Madrid player.. "We have to wait and see who comes in," he continued. "De Gea belongs to another club in Manchester United, one who we are friendly with. There won’t be another player who arrives at the club at nine and leaves 25 years later. He will always be a legend for us." Madrid have long been linked with De Gea but have yet to get their man and could be forced to wait to sign him on a free transfer next summer.