Dee ihe na-aga n'ihu maka paragraf a - N'ihi mkpọchi NHL nke 2012 <unk> 13, ndị Leafs tọhapụrụ Gunnarsson iji soro ndị otu obodo ya Örebro HK mee oge egwuregwu. Mgbe mkpọchi ahụ kwụsịrị, Gunnarsson laghachiri na North America wee gaa n'ihu n'oge ahụ na Toronto Maple Leafs. Agbanyeghị, oge ya n'usoro ahụ adịteghị aka ka ọ na-agwọ ọgwụgwọ iji weghachite mmerụ ahụ ikpere mgbe ọ na-egwu egwuregwu asaa. Gunnarsson ka enyere ikike igwu egwu maka Leafs tupu oge 2013-14 wee mee usoro mmeghe ha. Oge ahụ ga-abụ nke ikpeazụ ya na Maple Leafs, dịka na 28 June 2014, Gunnarsson na nke anọ na-ahọrọ na 2014 NHL Entry Draft
e resịrị ndị St. Louis Blues n'ọnọdụ onye na-agbachitere Roman Polák. A wara ya ahụ n'úkwù n'oge oge ezumike ma a kwadoro ya n'ụzọ ahụike ka ọ kpọọ na 14 Ọktoba 2014.