At the 2014 U18 World Hockey Championships, McDonald was named the tournament’s top goaltender – turning heads and catching the attention of the big leagues. On June 28th, Mason McDonald was drafted 34th overall by the Calgary Flames – the first goalie selected in 2014’s NHL Entry Draft. He entered the draft ranked number two among North American goalies by NHL Central Scouting. As a Calgary prospect, this past season, MacDonald stayed with the QMJHL’S Charlottetown Islanders for a third year where he posted a 21-15  record while registering a 3.33 goals against average.