Foster spent five years on the Old Trafford payroll before leaving for Birmingham in 2010.
And although that period included two seasons out on loan and another sidelined by injury, he still got a pretty good insight into what makes the mighty Old Trafford machine tick.
Foster accepts the heat is on Moyes following Ferguson's exit.
But he is confident United have the right man for the job.
"David Moyes has huge shoes to fill but I don't think anyone could have walked into that job and felt no pressure at all," he said.
"It is the biggest job in world football.
"United have made a good decision. Moyes has got that steel about him.
"From what I hear he is a hard character. He has high standards all the time.
"You see what he has done at Everton on a limited budget. He has eked out the last little bit of quality from every one of his players."