The Spaniard has struggled to adapt to life in the Premier League since his 2011 arrival, making a series of costly errors.
Fergie has persisted with the 22-year-old in spite of some shaky displays, but has now decided to search for alternatives in a bid to keep United’s title charge on course.
It is thought that a stopper who is eligible for to play in the Champions League is desired, rather limiting the Scot’s list of targets.
Stoke ‘keeper Asmir Begovich is believed to be one of his favoured options, after a string of impressive displays with the Potters this term.
He could also make a shock move for Liverpool star Pepe Reina, whose future at the club is far from certain following an underwhelming start to the campaign.
The Red Devils have chopped and changed between de Gea and back-up goalkeeper Anders Lindegaard, but neither has been able to fill the void left by Edwin van der Sar.
Fergie is thought to be worried about de Gea’s physical attributes and command of his area.