At the 2018 NHL trade deadline, the Montreal Canadiens essentially swapped Joe Morrow for Mikey Reilly, though the deals were separate trades. In 38 games, Morrow had had difficulties on defence, and the team was looking for an upgrade. Reilly was a good addition to a team shifting focus to the future, producing eight assists in his 19 games, and still being under contract for an additional season.
Still without a bona fide first-pairing defenceman on the left side, the Canadiens nonetheless entered 2018-19 with some competition for the three spots at that position.