Now nearing the end of his second season at Old Trafford, many observers believe it will be his last.
The summer arrival of Jack Butland at Stoke suggests Asmir Begovic will be on the move, with United long since being viewed as a likely destination.
That would free up De Gea for a return to Spain, ending the difficulties he has endured in the Premier League, with even former United defender Gary Neville turning against the 22-year-old following his blunder at Tottenham last month.
Yet, with Anders Lindegaard also looking shaky, Ferguson has opted to stand by De Gea.
And as he sat alongside the former Atletico Madrid man on Tuesday night, it was clear Ferguson felt a sense of responsibility for De Gea's development.
"David has shown his character because he has taken a lot of criticism, sometimes unfairly," said Ferguson.
"What we are good at is developing people. He came to us as a very young man, not used to the English game and unable to speak the language.
"Also he was still to mature physically.
"But it's like a young kid taking his first steps forward, he wobbles, then gets up, wobbles, then gets up again and eventually he walks. The boy is walking now."