Jasper Cillessen
Jasper Cillessen not for sale say Ajax (Getty)

Manchester United have been told to forget about signing Ajax goalkeeper Jasper Cillessen as a potential replacement for David de Gea.

De Gea, 24, remains heavily linked with a move to Real Madrid this summer with his manager Louis van Gaal unable to say for definite whether the goalkeeper will still be at Old Trafford next season.

Speaking to the press earlier in May, Van Gaal confirmed the club have drawn up a list of potential replacements for the Spain international, with Tottenham Hotspur's Hugo Lloris, Petr Cech of Chelsea and Inter's Samir Handanovic among those being considered.

On 19 May, though, the Mirror reported that Netherlands international Cillessen is at the top of the list on the advice of Van Gaal's long-time trustee and goalkeeping coach Frans Hoek.

But Ajax's director of football Marc Overmars has warned United their goalkeeper will not be sold for any price. "He is not for sale," he told de Telegraaf when asked of the report linking Cillissen to Old Trafford. "Not even for €25m."

Van Gaal selected Cillesen, 26, to start in each of Netherlands' games at the World Cup in Brazil last summer, but infamously replaced him with Newcastle United's Tim Krul for the quarter-final penalty shoot-out with Costa Rica, a decision vindicated when Krul made the winning save.

De Gea meanwhile picked up the awards for United's player of the season and players' player of the season at the club's end-of-season award ceremony on 19 May.

While questions of his future where kept off the table during the gala event, his reluctance to sign a new contract at the club has left United with little choice but to consider replacements.

"We have a list of goalkeepers who can replace him because we have to be organised always," Van Gaal said. "We want him to stay and I hope he shall sign.

"You have three parties [involved] and the most important party is always the player. It is dependable not of Manchester United, not of me, because we want him to sign. He has to sign, he has to want to stay here at Manchester United."