Maguire, 28, was handed the armband in January 2020 by former manager Ole Gunnar Solskjaer – just five months after joining United in a £80m move from Leicester.
Maguire has faced criticism for his performances this season and former United defender Ferdinand says the “massive responsibility” of the captaincy could be weighing heavily on the England international.
When asked if Maguire would have been dropped by now if he was not club captain, Ferdinand told Vibe with Five: "The fact that he has had the armband has given him that grace, which it would do.
"I think he was given it too early. It’s a hard enough job coming into Manchester United, getting your feet under the table and starting to feel comfortable as it is without the added pressure of being captain.
"Being captain is a massive responsibility, there is history that goes with it, a big weight on your shoulders.
"You need to experience being there for a period of time to carry that weight.
“It was more important for Maguire to come in and concentrate on becoming a Manchester United mainstay than being captain."
Ferdinand believes De Gea is a better pick for captain and would allow Maguire to concentrate solely on his own performance.
The Spanish goalkeeper is United’s longest serving player, having joined the club from Atletico Madrid in 2011.
Ferdinand added: "The thing you can counter that [Maguire criticism] with is that there weren’t many captains at the club - who else are they going to pick?"
"David de Gea would have been my choice because of the time he’s been there and he knows what it takes to win.
"This is all with hindsight but you have to got to think about these times that might come with someone like Harry Maguire, new at the club in that sense.
“And that added pressure is weighing on him heavily at the moment."
United are now seventh in the Premier League, four points off the Champions League places, following Tottenham’s dramatic win over Watford on Saturday.
Ralf Rangnick’s side next face Wolves on Monday before facing Aston Villa in the FA Cup on January 10.
