Rubuta ci gaba don wannan sakin layi - Saboda kulle-kulle na 2012 <unk> 13 NHL, Leafs sun saki Gunnarsson don buga wasan kakar wasa tare da ƙungiyar garinsu Örebro HK. Bayan rufewar ya ƙare, Gunnarsson ya koma Arewacin Amurka kuma ya ci gaba da kakar wasa tare da Toronto Maple Leafs. Koyaya, lokacinsa a cikin jerin sunayen bai daɗe ba yayin da ya sami magani don sake gyara raunin ƙugu bayan wasa a wasanni bakwai. Gunnarsson an share shi don yin wasa don Leafs kafin kakar 2013-14 kuma ya sanya jerin su na farko. Wannan kakar zai tabbatar da zama na karshe tare da Maple Leafs, kamar yadda a ranar 28 ga Yuni, 2014, Gunnarsson da zagaye na hudu na zagaye a cikin 2014 NHL Entry Draft
An yi musayar su zuwa St. Louis Blues a musayar mai tsaron baya Roman Polák. Ya yi aikin tiyata a lokacin hutu kuma an ba shi izinin likita don yin wasa a ranar 14 ga Oktoba, 2014.