Welch, 24, made just one appearance for the Wolves back in 2008, before moving to the USA with his family.
He said: “It was a very tough decision to leave Warrington and also put my rugby career at risk. I was dealing with some family troubles and at that time it was all just to much for me to handle. So I decided to leave and try to work things out.
“Since then I’ve matured as a person and as a player. I want to show what I can do on the pitch so I’m very excited that I’ve been selected for this World Cup. It’s the biggest stage to show talent. For me to get another shot at Super League would be a dream for me, but I’m also willing to put the hard work in and earn that chance.”
Welch has turned down an offer to play Rugby 7s for USA to commit his future to rugby league.
He has been playing in the domestic league competition back in the States.
He added: “This World Cup will be an amazing experience. To be playing among the sport’s top players and I get the chance to represent a nation as big as USA in their first ever league World Cup. To make it even better we’ll be near my old town where I grew up.
“I want to impress out there so I can aim for a chance to pick up my league career and push it forwards. I back myself but all I need is an opportunity.”