In the following 2015–16 season, on the eve of opening night on October 6, 2015, Harrison cleared waivers, and was reassigned to the Manitoba Moose of the American Hockey League. In returning to the AHL for the first time since 2010, Harrison appeared in 18 games with the Moose before he was included in a trade deadline deal by the Jets, along with Andrew Ladd and Matt Fraser to the Chicago Blackhawks in exchange for Marko Daňo and a first-round pick in the 2016 NHL Entry Draft on February 25, 2016. He was immediately assigned to the Blackhawks AHL affiliate, the Rockford IceHogs.