Mourinho 'not confident, not worried' about De Gea signing new contract
The Spain international goalkeeper's deal expires next year, although there is an option of a 12-month extension.
It was reported in June that De Gea had agreed to fresh terms with the club following speculation linking him with Real Madrid, but a deal was never announced.
Now, Mourinho has cast doubt on the 27-year-old's future by admitting he is uncertain talks will reach a positive conclusion.
"I am not confident, but I'm also not worried," the United manager told Sky Sports. "I cannot find the word in English, but let's see what happens.
"Only the club, David and his people can answer that. My comment is only that everyone knows how good he is, how important he is for Manchester United and if the club want to be better than it is and not worse, obviously it would be very important to keep David."
Madrid were long linked with De Gea, having failed with an attempt to get him in 2015, shortly before he signed his latest contract extension.
However, the signing of Thibaut Courtois from Chelsea makes it unlikely the LaLiga giants will renew efforts to bring De Gea back to Spain.
Juventus have recently been tipped to try to sign the former Atletico Madrid man next year, possibly on a free transfer.
Cos we are @ManUtd pic.twitter.com/ht9JEuxRF8
— David de Gea (@D_DeGea) October 7, 2018