David de Gea is not irreplaceable at Manchester United as doubts remain over his future, according to former Red Devils goalkeeper Edwin van der Sar.
De Gea has been tipped to sign a new long-term contract with United, however, the star goalkeeper is yet to commit to the struggling Premier League giants.
The Spain international – who arrived from Atletico Madrid in 2011 – is out of contract at the end of the season and has been linked to Serie A champions Juventus as his reported contract offer remains unsigned.
Van der Sar – now Ajax's chief executive officer – won four Premier League titles and the Champions League during his time at United and the 48-year-old said De Gea is not indispensable despite his quality.
"Other goalkeepers can also fill the gap," said Van der Sar, who has been linked with a return to United as a sporting director, though the Dutchman has dismissed speculation.
"There are a few Premier League goalkeepers playing at the club who can also take the step up.
"I was 34 when I went to United, so there are lots of opportunities there.
"The decision needs to come at a certain point. It's taken a long time now, so it's a case of 'yes' or 'no' but I'm not a director of United."
De Gea's form has been questioned after a number of errors at the end of the 2018-19 season, while he could have done better for Crystal Palace's last-gasp winner against United last month.
However, Van der Sar added: "That happened to me, it happened to [Ryan] Giggs also, to everyone.
"Your form differs. He has been for so long at such a high level, so at a certain point it gets noticed [when your form dips], maybe not the first two times, but then people start to write about it. But he'll be fine. He's a great goalkeeper."
United – who have only won one of their opening four matches – are back in action at home to Leicester City on Saturday following the international break.