That is according to United legend Ryan Giggs.
The former Red Devils winger was Louis van Gaal’s assistant at Old Trafford when Keane was pushing through from United’s academy.
But the 24-year-old never really earned an opportunity to flourish in the first team.
Michael Keane earned his senior England debut last night, just over two years since leaving Man Utd
With Chris Smalling and Phil Jones at the club, Van Gaal also brought in Marcos Rojo and Daley Blind to bolster his defence.
As a result, Keane was allowed to join Burnley on a permanent deal.
Since the switch in 2015, the centre-half has established himself as a star figure in the Premier League.
Daley Blind and Marcos Rojo's arrival at Manchester United saw Michael Keane leave for Burnley
England player ratings against Germany
Wed, March 22, 2017
Express Sport brings you England's player ratings from their defeat to Germany
Get Quotes on Home Insurance
1 of 11
Joe Hart – 6
Louis [Van Gaal] had brought in Marcos Rojo, Daley Blind, so he wasn't playing
Last night, Gareth Southgate named him in his starting XI for England in their friendly away to Germany.
And Giggs, a pundit for the game, has been impressed by Keane’s progress.
Giggs told ITV Sport: "At the time we had [Chris] Smalling, we had [Phil] Jones.
"Louis [Van Gaal] had brought in Marcos Rojo, Daley Blind, so he wasn't playing.
Burnley centre-half Michael Keane impressed for England against Germany
"Credit to him, like I say, he's gone away, knuckled down.
"He deserves his chance, because he's been consistently good in the Premier League.”
Keane shone in England’s defence on his senior debut in the 1-0 defeat.
And his strong form has reportedly attracted attention from Liverpool ahead of a potential summer move.