 In the playoffs, Mason started 4 games and played in 5, going 2-2 with a 1.97 GAA and a .939 save percentage, but the Flyers were eliminated by the New York Rangers in 7 games.On July 1, 2017, as an unrestricted free agent from the Flyers, Mason signed a two-year deal with the Winnipeg Jets worth $8.3 million.On June 30, 2018, Mason was traded to the Montreal Canadiens along with forward Joel Armia and a few draft picks for defenceman Simon Bourque.