Guzan didn't take goalkeeping seriously until his teens.
He told the Sunday Mercury: "Before I went to University, for my club team in America back in Chicago, I played as an outfield player, probably because I was one of the biggest guys on the field.
"I was about 17 and I played in a national final.
"I just didn't have the speed or the ability to carry on playing outfield at university level, so into the goal I went and here I am.
"I'd trained as a goalkeeper as well, probably from about 12 onwards.
"My older brother was a goalkeeper so as a kid growing up I always saw him playing as a goalkeeper.
"I used to play almost as a holding midfielder, in front of the defenders, as a kind of stopper back kind of thing. I used to go round smashing people."