The Red Devils goalkeeper has been one of Manchester United’s most consistent players over the past four or five seasons.
Indeed, Spanish shot stopper De Gea is widely recognised as Manchester United’s one undoubted world-class talent.
The 27-year-old goalkeeper has been regularly linked with a move to La Liga giants Real Madrid over the past few summer transfer windows.
De Gea was on the brink of a move to los Blancos in the 2015 summer transfer window before a deal fell through due to paperwork.
The Manchester United goalkeeper has been linked with a return to Madrid in the last two summers but De Gea has remained at Old Trafford.
Former Chelsea FC defender Burley believes Mourinho could quit Manchester United if their best player is allowed to leave.
“I think De Gea will stay,” Burley told ESPN FC.
“If Man United sell him, Mourinho could walk. He is their best player.
“They can ill afford to allow him to go to Real Madrid. They don’t need the money.”
Manchester United finished in sixth place in the Premier League table last term in Mourinho’s first season in charge.
The Red Devils won the Europa League and the League Cup under the Portuguese head coach.
Manchester United signed Chile international Alexis Sanchez in a swap deal from Arsenal in the January transfer window.
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