Kammala jumla mai zuwa: A matsayin dan wasa mai kyauta a cikin kakar wasa, McKenna ya tsawaita aikinsa ta hanyar amincewa da kwangilar shekara guda, kwangilar kwangila tare da Ottawa Senators a ranar 1 ga Yuli, 2018. Ya shiga kungiyar AHL, Belleville Senators don fara kakar 2018/19. Bayan wasanni shida tare da Belleville, Ottawa ta sake kiran McKenna. Ya bayyana a wasanni 10 tare da Sanatoci, yana yin rikodin 1-4-1 kafin a yi ciniki tare da Tom Pyatt da kuma
Zaɓin zagaye na shida na 2019 zuwa Vancouver Canucks a musayar Anders Nilsson da Darren Archibald a ranar 2 ga Janairu, 2019. An yi watsi da shi bayan ya goyi bayan Jacob Markström na wasanni biyu, tare da niyyar Canucks ta sake sanya shi ga AHL affiliate, da Utica Comets. Philadelphia Flyers sun yi da'awar sa da sauri yayin da suka magance raunin da ya faru ga masu tsaron gida Brian Elliott, Michal Neuvirth, da Anthony Stolarz. McKenna ya fara wasan Flyers a ranar 8 ga Janairu, 2019 a kan Washington Capitals. Shi ne mai tsaron gida na bakwai da ya fara Flyers a cikin kakar 2018/19 a cikin wasa na 43 kawai. A ranar 30 ga Janairu, 2019, McKenna ya amince da rance na kwanaki 14 tare da Lehigh Valley Phantoms. Ya tafi 2-1 a lokacin aikin yayin wasa don rikodin AHL na goma sha uku.