The forward, who's scored 698 goals in his 15 NHL seasons, has no points in his past five games after having 15 points (14 goals, one assist) in his previous seven.
Ovechkin has 54 points (32 goals, 22 assists) in 49 games against Montreal.
The Capitals, 3-6-0 in their past nine games, trail the Pittsburgh Penguins by one point for first place in the Metropolitan Division.
Defenseman Brenden Dillon, acquired in a trade with the San Jose Sharks on Tuesday, is expected to make his Washington debut on the first pair with John Carlson.
The Canadiens, on a five-game winless streak (0-4-1) after going 5-1-0 in their previous six, are 10 points behind the Carolina Hurricanes, New York Islanders and Columbus Blue Jackets for the first wild card into the Stanley Cup Playoffs from the Eastern Conference.