Foster was working as a chef and playing non-league football for Racing Club Warwick when spotted by Dobson.
He joined Stoke although he never played a game for them before moving to Manchester United and then Blues via a loan spell at Watford.
Foster is currently in outstanding form and produced a superb save to deny Carlton Cole in the weekend draw with West Ham.
But the England player knows it might have been all different had he not been spotted by Dobson.
Foster said: "I was working as a chef in addition to training on a Tuesday night and playing on a Saturday.
"There was a scout called Colin Dobson who worked for Stoke but was living in Warwick.
"One night, he's told me, he saw some floodlights, stopped off and had a little watch of the game - and I caught the eye.
"That was it. He made a note of it and came to watch me a few more times and things went on from there.
"I see him all the time. I have got his phone number. I owe it all to him."