After completing a 65-point season for the Cougars in 2007–08, Tyrell was assigned to Tampa's American Hockey League (AHL) affiliate, the Norfolk Admirals. He appeared in 11 games for Norfolk, scoring one goal and five assists to complete his season. The Lightning returned him to junior to complete his 19-year-old season in 2008–09, and with 40 points in 30 games, was named to the Canadian team for the 2009 World Junior Ice Hockey Championships. He never appeared in a tournament game, however, suffering a knee injury in an exhibition game against Sweden prior to the tournament. The injury required surgery to repair torn ligaments, and ended his season.