Virtanen was selected 6th overall in the 2014 NHL Entry Draft by the Vancouver Canucks. He was the first British Columbia born player selected in the first round by the Canucks since Cam Neely in 1983. On July 25, 2014, Virtanen announced he had signed an entry-level contract with the Canucks via Twitter. When posting about his deal he said,"such an honour to sign with the Vancouver Canucks! I'd like to thank everybody who's helped me get to this point especially my family!!" He returned to the Hitmen for his final year of major junior hockey before being reassigned to the Canucks' American Hockey League (AHL) affiliate, the Utica Comets, following their WHL Playoff elimination. Virtanen immediately joined the Comets' 2015 Calder Cup playoffs lineup on May 18, where he made his professional debut during Game 6 of the Western Conference Semifinals. Following the 2–1 loss to the Oklahoma City Barons, he said it was "a great experience and exciting time with a great group of guys. The guys up here are a lot bigger and the game is faster. The game was exciting and the fans were amazing up here. The atmosphere in the rink is incredible." He continued to play with the Comets during their postseason push, eventually recording his first professional assist on a Sven Bärtschi goal in Game 3 of the Western Conference Finals against the Grand Rapids Griffins.