Former Manchester United player Phil Neville has urged the club to tie David de Gea down to a new long-term contract.
De Gea has been strongly linked with a move away from Old Trafford this summer, with European champions Real Madrid understood to see the Spaniard as a natural successor to Iker Casillas.
The 24-year-old's current contract expires at the end of next season and, with talks over an extension still ongoing, Neville fears that the shot-stopper could depart.
"My biggest fear in the summer is David de Gea. I want him tied up on a long-term contract," Neville told the club's official website.
"He is the best developer I have seen for a number of years. From where is when he first signed to where he is now, the development and the improvement he has shown has been nothing short of incredible.
"He is the best around. He has won Manchester United games, he is up there with [Edwin] Van der Sar and [Peter] Schmeichel in terms of winning games so that would be my one worry this summer."
De Gea was named in the PFA Team of the Year last month having helped United to the brink of a Champions League return this season.