Whakaotihia te rerenga e whai ake nei: I te wa o te tau 2015-16, i kaha a Cowen ki te whakakaha i a ia i roto i te rarangi o Ottawa, i etahi wa ka kite ia i a ia ano he pakaru hauora. I te Hui-tanguru 9, 2016, i whakauruhia a Cowen ki roto i te tauhokohoko, e iwa nga kaitakaro me te Toronto Maple Leafs. Ko Cowen, ko Colin Greening, ko Milan Michalek, ko Tobias Lindberg, ko Ottawa's
I tukuna te whiringa tuarua o te tau 2017 ki Toronto hei utu mo te rangatira o Maple Leafs a Dion Phaneuf, Matt Frattin, Casey Bailey, Ryan Rupert me Cody Donaghey. I te Hui-tanguru 26, 2016, i tukuna a Cowen ki runga i nga herenga e nga Maple Leafs ka tukuna ki ta raatau hononga AHL, ko te Toronto Marlies. I tukuna a Cowen ki te kaainga e Toronto ki te tatari i te hoko me te tuku i te herekore ki te whakapiri atu ki etahi atu roopu mo tetahi kirimana hou mo te waa 2016-17; Ko te hoko i te kirimana a Cowen ka whakawhiwhia ki nga Leafs ki te $ 650,000 utu utu mo te waa 2016-17.