Sydney-born Stein, 25, joined GWS as a category B rookie at the end of 2016 and has developed as a defender after being scouted by the Giants' inaugural high performance manager John Quinn.

Stein, who was disqualified from the decathlon at the 2014 Commonwealth Games in Glasgow after false starting twice in the 100m sprint, is hoping for a smoother introduction to AFL against North Melbourne in Hobart on Sunday.

GWS coach Leon Cameron had no doubt Stein, who replaces the injured Nick Haynes, could make a successful transition.

"He's a great story. He was found in athletics, he's from Penrith in Western Sydney. His development has been phenomenal," Cameron said.

"Jake's got a really big motor, he's got elite speed and he's really worked on the nuances of the game to learn about body positioning and spoiling," he said.

Cameron added Stein was now the ultimate team player after years of competing at an individual level.

"We're rapt and there was a huge roar when we told the group," he said.

"He will take up the key back position against some really quality key forwards in the Kangaroos.

"We're really confident Jake is going to come out and play his role."

Stein, who won the club's NEAFL development award last season, was second in the decathlon at the world junior championships in Spain in 2012 and a year earlier he won octathlon gold at the world youth championships in France.

Australian Associated Press