Tyrell was a fifth-round selection of the Prince George Cougars in the Western Hockey League (WHL) Bantam Draft in 2004. He appeared in one game that season before establishing himself as a regular with the Cougars in 2005–06. He scored 30 goals in his second full season, and was selected in the second round of the 2007 NHL Entry Draft by the Tampa Bay Lightning. Additionally, he made his international debut for the Canadian junior team at the 2007 Super Series, scoring one goal in eight games, but failed to make the team for the 2008 World Junior Ice Hockey Championships.