In the new NHL, McDonald was picked up by the Montreal Wanderers. McDonald was one of 12 players who were members of the 1917–18 Wanderers' squad. The Wanderers home arena was destroyed by fire only 6 games into the 22 game schedule. This event forced the league to disperse the Wanderers players via a draft to 1 of the remaining 3 teams (Toronto, Montreal Canadiens and Ottawa Senators) in the National Hockey League. McDonald was picked up by the Montreal Canadiens for whom he played until 1919, including the ill-fated 1919 Stanley Cup Finals which was cancelled after five games (tied at 2-2, with one tied game) because of the Spanish flu pandemic. McDonald was one of the Canadiens players seriously ill with the flu when the series was called off. His teammate Joe Hall would succumb to the illness.