Any extended absence could be devastating to the Maple Leafs and the NHL as a whole because of the excitement Matthews brings on the ice.
The 21-year-old center is considered one of the best young players in the sport after being selected with the first overall pick in the 2016 draft. He burst on to the scene with 69 points in his first year, winning the Calder Trophy as the best rookie in the league.
He remained an impact player in his second season with 34 goals and 29 assists in just 62 games, although he missed about a month through injury.
He has played well this season, with 10 goals and 6 assists, and the Maple Leafs will have to figure out how to win without him.
John Tavares' addition will help Toronto handle the loss, but Mitch Marner and Nazem Kadri will also have to step up in Matthews' absence.