Manchester - Manchester United manager Jose Mourinho is "not confident" that goalkeeper David De Gea will sign a new contract when his current Old Trafford deal expires.
The 27-year-old Spain international is now regarded as one of the best keepers in world football, having joined English giants United from Atletico Madrid in 2011.
He was, however, close to joining Real Madrid before a proposed move to the Bernabeu collapsed in 2015.
De Gea then signed a renewed contract that will see him stay with United until 2019, with the option to extend by an extra year.
With former Chelsea goalkeeper Thibaut Courtois signing for Real in pre-season, it looks as if a return to the Spanish capital is no longer an option for De Gea, but he has been linked with a move to Italian club Juventus.
"I am not confident," Mourinho told Sky Sports ahead of United's match against Everton on Sunday when asked about the prospects of De Gea staying at Old Trafford.
"I am not worried. I am not more than worried. I cannot find the word in English," the Portuguese boss added.
"Let's see what happens. Only the club, David and David's people can answer to that."
United have not won the English Premier League title since legendary manager Alex Ferguson retired in 2013 and Mourinho's men are nine points adrift of leaders Manchester City, the reigning champions, heading into this weekend's fixtures.
Mourinho insisted De Gea was the type of player United had to retain if they were to challenge for the title again.
"My comment is only one: everybody knows how good he is, everybody knows how important he is for Manchester United," he said.
"And if Manchester United wants to be better than it is now and not worse than it is now, obviously that would be very important to keep David."