Indeed, the Aussie says De Gea might not get the deal he wants with mistakes creeping into his game.
He told Goal: "They will have to come to a decision at some point on whether his value is the same as what he is asking for.
"There's speculation about him and then there's the fact that he may still choose to leave.
"Ultimately there comes the point where your history and your past performances only get you so far. It is about now. If you look at his last six months, his average performances haven't been anywhere near what they have been in the past.
"If you break it down, a lot of goals have come from direct mistakes from De Gea. Probably more than in the entire six or seven-year period before. There is always a balancing act as a player. What's your current value? Your recent performances come into that.
"Can he get to the level he was at before? Part of that is being consistent. Consistency is not a word I would associate with David de Gea over the last six months. If not more."