With the dust still settling on the Red Devils' first FA Cup win since 2004 - and first trophy in three years - the Dutchman was shown the door on Monday.
Speculation has been rife for months that former Chelsea boss Jose Mourinho would replace his old mentor at the club, with Monday's events only adding fuel to the flames, as reported by the likes of Sky Sports.
While van Gaal delivered some long-awaited - by Manchester United's high standards anyway - silverware, a fifth place Premier League finish was not good enough to secure the holy grail of Champions League football.
The side's style of play has been under scrutiny for some time too with former players such as Paul Scholes critical of the methodical, possession-based football favoured by the former Holland boss.
Ferdinand defends key element of van Gaal tenure
"He (van Gaal) is huge personality who won an FA cup, keeping up his habit of winning trophies everywhere he has been," Ferdinand wrote on Facebook.
"But his Manchester United legacy will be the introduction of the players from the academy like Rashford, Lingard, Fosu-Mensah etc which WAS in keeping with the history of the club - giving kids an opportunity to play."
A question of style
Ferdinand was equally critical of the way in which United have played the last two seasons in his comments.
The man who was the foundation upon which the club won their last Champions League trophy said the vastly experienced Dutchman failed to deliver the 'attacking, quick, aggressive and imaginative style of football' the club demands.
He also added that he respected him for sticking to the beliefs that have brought him success and trophies wherever he has been in his career.
Champions League or bust for new man
Whether a new manager, like a Mourinho, can now take the club back to its former glory remains to be seen.
But we now know that anything less than Champions League football for whoever does replace van Gaal could cost that replacement his job in an increasingly competitive Premier League.