Matthews set the unofficial NHL record for most consecutive games with a shot on goal to start a career. His 103-game streak ended in a 4–1 victory over the Calgary Flames on November 28, 2017. On December 9, after colliding with a teammate during a game against the Pittsburgh Penguins, Matthews missed six games to recover from a concussion. On January 10, 2018, Matthews was selected as the sole Maple Leaf to participate in the 2018 NHL All-Star Game. On February 24, it was revealed that Matthews had suffered a shoulder injury and would be out for at least ten days. However, he did not return to the Toronto lineup until March 22, 2018, where he scored a goal in the second period to help the Leafs win 5–2 over the Nashville Predators. Despite missing 20 games, Matthews finished the regular season with 34 goals and averaged over one point per game. The Maple Leafs qualified for the Stanley Cup playoffs for the second consecutive season but were eliminated in the first round by the Boston Bruins. He was not particularly productive in his second playoff run, finishing with one goal and one assist in seven games.