The Flyers' first priority is clinching a playoff spot, but they also want to overtake the New York Rangers and finish second in the Metropolitan Division, giving them home-ice advantage in the opening round.
The second-place Rangers have a two-point lead on the third-place Flyers, who have two games in hand.
The Flyers have eight games remaining, including Tuesday's difficult matchup in St. Louis, while New York has six games left.
The Flyers play five teams in the playoff hunt; the Rangers play just two teams (Colorado and Montreal) that figure to make the playoffs.
Under the NHL's new format, the second- and third-place teams will face each other in the opening playoff round. A Flyers-Rangers matchup appears likely.