Zub, 24, spent the 2019-20 season with SKA St. Petersburg of the Kontinental Hockey League (KHL), where he established professional career highs in goals (13), assists (nine) and points (22) while tying for the KHL lead with a plus-35 plus/minus rating over 57 games. His goals and points' totals led St. Petersburg defencemen while his 13 tallies were tied for second most by a KHL defenceman. He also ranked fifth among SKA players in scoring.