Foster revealed that he was in fact grateful for his time at Manchester but he became frustrated at the lack of first team action he was receiving.
"Some of the times at United, I didn't enjoy. It's a very difficult football club from any other I've been at. It's very cut-throat. It's success at all costs. I love winning, I really do - anything I do, if I'm playing well at home with my missus, I want to win - but it got to a point where I didn't enjoy it.
What Foster says is true, however he did have a spell in 2007 where everything was going his own way. Loaned out to Watford to gain first team action Foster's display of dominance earned him an England call-up and a debut against Spain in February of 2007. He continued to impress and showed no sign of slowing down as he was rapidly evolving as quite a young talent amongst English football.
After that successful loan at Watford he returned to United in search of regaining a first team place but he once again lost out to United veteran Edwin van Der Sar. He started to become increasingly frustrated at the lack of first team action playing every once in a while, often in the 'dead rubbers'.
"I couldn't get my head around the fact you'd play once in a blue moon and then be expected to come back in and do it again. I couldn't deal with that.When I'm playing week in, week out, that's when you know you love what you are doing."
2009 was another big year for the Englishman as he was given a rare start by manager Sir Alex Ferguson in the Carling Cup final against Tottenham. He displayed an account of dominance as he was crowned man of the match for his penalty shoot-out save from hapless Jamie O'Hara with David Bentley squandering his opportunity, shooting wide giving United the Carling Cup.
In late 2009 United keeper Edwin van Der Sar became incapable of a place of a starting team due to hurting himself saving a pre-season penalty. Foster quickly became favourite at Old Trafford but various mistakes against the likes of Arsenal and Manchester City cost him his place. When Van Der Sar returned Foster's chances of first team football once again diminished as he was once again forced to take a place on the bench.
Then in May 2010 a glorious chance for first team football came knocking for Foster. Birmingham City were in need of a replacement keeper following Joe Hart's return to home club Manchester City. City paid United a then bargain £4 million and Foster couldn't have been more happy. He is now playing in a regular role for the Midlands side and recently starred in a magnificent performance for Birmingham, making a string of superb saves when they miraculously managed to beat champions Chelsea 1-0.
"I get such a buzz from knowing I'm going to be playing every week. You see players who are playing one week but might be rested the next. I like to know what I'm doing, to feel I'm an important part of the team, that feeling that you're needed in the team, so you rise to that as well."