Glass spent his junior career with the Kootenay Ice of the Western Hockey League (WHL), spending three seasons with the team from 2002–2005. At the conclusion of the 2004–05 season, Glass won the Del Wilson Trophy as the WHL's top goaltender, was named to the WHL First All-Star team, and was named CHL Goaltender of the Year as the best goaltender in Canadian major-junior hockey. That year, Glass was also named starting goaltender for Canada at the 2005 World Junior Championships in North Dakota. Glass went 5–0 with a 1.40 goals against average (GAA), backstopping Canada to its first gold medal at the tournament since 1997.