The Capitals, winners of four straight, trail the Flyers by one point and could overtake them for third place in the division with a regulation victory. Washington has not held that position since Jan. 16.
Though the two-game set holds significant importance for both teams' postseason aspirations, the Capitals are focusing on what lies in front of them Sunday.
"Obviously it's an important game, but if we win, great, and then we've got to play them again [Wednesday]," coach Adam Oates said. "Right now, we're still, I think, in the process of playing every game as it is. Today, we play Philly. Let's worry about Philly today."
Each team enters the first matchup this week having won Saturday matinees. Washington earned a 4-2 victory against the Boston Bruins and Philadelphia defeated the New York Rangers by an identical score.
Philadelphia will be tasked with slowing down a Washington offense that has rediscovered its potent touch. In winning seven of 10, the Capitals are averaging 3.7 goals per game over that span compared to 1.14 during the seven-game winless streak that preceded it.
Specifically, Alex Ovechkin has dispelled any concerns of a 2014 Sochi Olympics hangover. The NHL's leading goal scorer has three goals and five points in two games after scoring just once in five Olympic games for Russia.
Here are the projected lineups for the Flyers and Capitals:
Injured: Ray Emery (lower body)
Scratched: Casey Wellman