Kammala wannan magana: Theodore ya fara aikinsa na hockey na kananan yara tare da Ƙungiyar Hockey na Ƙananan Aldergrove, a lokacin da ya kafa kansa a matsayin dan wasa mafi ban mamaki a cikin tarihin ƙungiyar. Nasarar da ya samu a cikin 'yan wasa ya sa ya sami zaɓi a cikin WHL Bantam Draft na 2010, ta Seattle Thunderbirds. A lokacin da yake aiki tare da kungiyar, Theodore ya zama kyaftin kuma ya yi gasa ga Team Canada a wasannin kasa da kasa daban-daban. Ya lashe lambar zinare a 2013 IIHF World U18 Championships da kuma
Gasar Hockey ta Duniya ta Junior ta 2015 da lambar azurfa a Gasar Cin Kofin Duniya ta IIHF ta 2019.