Philadelphia Union will return home on Sunday night to take on Houston Dynamo at PPL Park as part of MLS Soccer Sunday with kickoff scheduled for 7:00 PM EST (TV: MLS LIVE, Fox Sports 1). Dating back to 2013, Philadelphia has not beaten Houston and has only managed to secure two points in the last five matchups between the two sides.

What are the keys things to watch in this game?

For Houston, their roster, specifically their defense, has been ravaged with injuries coming into Sunday’s game. Defenders Jermaine Taylor, DeMarcus Beasley as well as Kofi Sarkodie will all be most likely out with injuries against Philadelphia. To add to this long list, Dynamo defender Raul Rodriguez will also be out due to a yellow card accumulation suspension.

According to the Dynamo’s official roster, with four defenders out, there are only four defenders remaining on the roster for selection. Houston midfielder Alex has played fullback in a few games this season, but all signs are pointing to him being unavailable Sunday due to a hamstring strain.

One possible glimmer of light for Houston will be former Union fullback Sheanon Williams, who was traded earlier this season. Williams, a member of the Union for five seasons, certainly knows how this Philadelphia Union team operates tactically, in addition to how to exploit possible weaknesses against his former club.

One interesting note to point out will be if Williams starts at right back, then he will be most likely going against former fullback pairing member and friend, Ray Gaddis. Given Sheanon’s penchant for getting forward, these two will likely come head to head at some point during this game.

For Philadelphia, the story is the opposite. Central attacking midfielder Cristian Madiana will be returning from his two game suspension. In addition, Maurice Edu could be available for selection after being a reported full participant in training on Wednesday. With Maidana returning, Tranquillo Barnetta will return to the wings to allow the MLS leading assist giver, Maidana, to be slotted into his more natural position.

The key to watch is how Maidana, Barnetta and Vincent Nogueira work with each other. Arguably the best three midfielders on the roster, the trio has not been able to stay on the same field for more than a couple of games. With the U.S. Open Cup Finals only two weeks away, these three will need to log minutes together to help build some rapport as well as consistency among the starting eleven.

Maurice Edu’s possible return poses Philadelphia Coach Jim Curtin an interesting dilemma going forward. Currently, at centerback, Richie Marquez and Steven Vitoria have both been solid enough in the back. Considering Edu’s more natural position is as a central defensive midfielder, Curtin could opt to keep Vitoria and Marquez as the centerbacks, while inserting Edu in the lineup for Brian Carroll.

Despite both teams having relatively little to no chance at making the playoffs, neither team will let their foot off the pedal with three necessary points on the table to keep those hopes alive.