The Spain international has been heavily linked with a move to the Champions League holders with negotiations over a new United deal failing to reach a satisfactory conclusion.
Real Madrid are believed to be interested in a move for the Red Devils number one as Los Blancos seek a replacement for struggling club legend Iker Casillas.
Former Rangers midfielder McCann told Sky Sports News that he wouldn’t be surprised to see the 24-year-old complete a move to the 10-time European champions.
“I think that will happen. I think De Gea would like to go to Real Madrid. I don’t think he’ll be best pleased by how things are going at Manchester United.
“Casillas is a top-class goalkeeper. We’ve seen him for generations playing at the very top and he’s won everything there is to win in the game.
“But he’s making mistakes that top goalkeepers don’t make. There are little saves that normally he pushes wide and doesn’t give any opportunities to strikers to follow up – but he is palming them into areas where strikers are sniffing around and scoring goals past him.
“I think there just seems to be a lack of confidence in his game at the minute and every sportsman needs confidence, but not only has he been affected, but the back four are conceding goals and the midfield looks as if they are not playing as a unit with the back four.
“It’s a team thing, but he has been highlighted. If a goalkeeper makes mistakes it’s in the back of the net and I don’t think it will be long before Real Madrid make a serious bid for De Gea.”
De Gea won the Premier League title in 2013 after the goalkeeper joined United in a £18m deal from Atletico Madrid in 2011.
The former los Rojiblancos man has made 158 appearances for United during his four-year stay at the Manchester club.
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