Mezue ahịrịokwu na-esonụ: N'etolite na Michigan, Joshua na-egwu hockey ndị na-eto eto maka Honeybaked U16 midget team ma kpọọ ya oku na USA Hockey Select National Team Evaluation Camp. Mgbe oge 2011-12 gasịrị, ndị Sioux Falls Stampede wepụtara Joshua na agba nke atọ nke United States Hockey League (USHL). Mgbe o kewara oge 2012/13 n'etiti Honeybaked na USHL, Joshua bụ onye Plymouth Whalers wepụtara na 156th n'oge Ontario Hockey League Priority Selection. N'agbanyeghi na edepụtara ya, ọ gara n'ihu na-egwu na OHL maka oge 2013-14 ma bụrụ onye nke 157 n'etiti ndị North American skaters site na NHL Central Scouting Bureau. E mechara họpụta Joshua na agba nke ise, nke 128 n'ozuzu, na
2014 NHL Entry Draft site na Toronto Maple Leafs. Ọ maghị na a kpọwo ya ruo mgbe o nwetara oku fon site n'aka ndị na-elekọta Toronto mgbe ọ nọ n'ụgbọala. Mgbe ọ họpụtachara Joshua, onye ndu ndị Leafs bụ Dave Morrison kwuru okwu ọma banyere ya dịka onye ọkpụkpọ, na-asị: "Ọ dị ogologo, na-eme egwuregwu nke ukwuu ma anyị hụrụ ụfọdụ ọkụ nke ezigbo nkà dị mma na njedebe afọ. Ndị na-enye ya ọzụzụ enweghị ike ikwu okwu ọma banyere ya. Ọ na-arụsi ọrụ ike n'ụzọ abụọ nke egwuregwu ahụ, onye ọkpụkpọ nwere ike itoolu. " Joshua nọrọ oge abụọ zuru oke na Stampede, n'oge ọ na-enyere ha aka imeri asọmpi iko Clark Cup nke 2015.