Kammala wannan jumla: A watan Mayu 2015, an kira Marshall a cikin tawagar 'yan wasan Ireland na Emerging don
Kofin Tbilisi na shekarar 2015. Kafin gasar, Marshall ya kasance wani ɓangare na Ireland XV wanda ya ɗauki Barbarians a Thomond Park. Ya bayyana a matsayin wanda zai maye gurbin Dan Tuohy, amma ya kasance a bangaren da ya yi rashin nasara yayin da aka doke Ireland 22 zuwa 21. Marshall ya fara wasan farko na Tbilisi da Emerging Italiya, ya fito daga benci a wasan na gaba da Uruguay kuma ya fara wasan karshe da Georgia mai masaukin baki yayin da Ireland ta lashe gasar a karon farko.