Fleury will try to become the 13th goaltender with 400 wins, and third active, joining Roberto Luongo of the Florida Panthers (467) and Henrik Lundqvist of the New York Rangers (430).
The Golden Knights, who are going for their third straight win, lead the Pacific Division with 93 points, 12 ahead of the second-place San Jose Sharks. They're five points behind the Nashville Predators for the most in the Western Conference.
The Flyers can move into a tie with the Washington Capitals for second place in the Metropolitan Division with a win. They're two points behind the Capitals (who host the Winnipeg Jets on Monday) and three behind the first-place Pittsburgh Penguins.