In the 2015–16 season, Matthias made his Maple Leaf debut on opening night in a 3-1 defeat to the Montreal Canadiens on October 7, 2015. Throughout the year, Matthias failed to score at a pace similar to his prior season in Vancouver, but was still seen as a decent producer given his role on the team. After contributing with 17 points in 51 games, on February 21, 2016, Matthias was traded by the rebuilding Maple Leafs to the Colorado Avalanche in exchange for a 4th round pick in the 2016 Entry Draft and prospect Colin Smith.