Grebenkin was promoted from AHL Toronto on Wednesday.
The decision to bring up Grebenkin comes as the Leafs placed Max Domi (lower body) on injured reserve in a corresponding move. Assuming the 21-year-old Grebenkin gets into the lineup against Vegas on Wednesday -- which seems like a safe bet considering the team doesn't have any extra forwards available -- it would mark his NHL debut. With the Marlies this season, the Russian winger has been rolling offensively with four goals and six assists through 13 minor-league games.