It's do or die for the Houston Dynamo, who cling to the final Eastern Conference playoff spot by just a single point.
Dominic Kinnear's squad is on 50 points with just two games left to play. If the Dynamo win their final two games against Philadelphia and Colorado, they will ensure themselves a postseason berth.
Anything less would then require a slip-up from either Columbus or New York.
This will be the third meeting between Houston and Philadelphia in 2012. Houston took the first game of the year 2-1 at the new BBVA Compass Stadium. The Union got revenge with a 3-1 steamrolling at PPL Park just three weeks ago.
Watch: Houston preview
Philadelphia is now 3-3-2 all time against Houston.
A 4-4-2, or 4-3-3?
The story in Houston this year is the tactical change implemented by Kinnear midway through the season. Traditionally a 4-4-2 team, the Dynamo are now capable of playing a more free flowing formation that focuses on passing and movement, as opposed to long balls and set piece opportunities.
Kinnear used the 4-3-3 in the Dynamo's most recent result, a 1-1 home draw with Montreal. Mac Kandji and Calen Carr played wide in the three pronged attack that focused on point man Will Bruin. Bruin is Houston's leading goal scorer with 12 tallies this season.
Ricardo Clark, Adam Moffat, and Oscar Boniek Garcia rounded out a three man midfield behind those forwards. Veteran Brad Davis was not available with a calf strain. Houston's leading assist provider (12 this year) is listed as questionable for Saturday, but Union manager John Hackworth expects him to play.
Houston deployed the same formation in the Sept. 23 game at PPL Park, but the personnel choices were a bit different. In that matchup, Boniek Garcia played higher up the field, with Luiz Camargo at right midfield and Davis on the left.
Look for any combination of Bruin, Kandji, Boniek Garcia, and Carr up top. Brian Ching and Cam Weaver provide forward depth off the bench, and give Houston a great late-game advantage in dead ball situations.
Houston is boosted by the return of 2011 all-star fullback Corey Ashe. Jermaine Taylor had been covering for Ashe at left back in recent weeks.
Centrally, Kinnear paired Taylor and Bobby Boswell against Montreal. He also has the option of using Andre Hainault at CB, or re-inserting him at right back, where he played earlier in the season. The right fullback spot is currently occupied by second year product Kofi Sarkodie, who has provided some nice defensive depth during Houston's run through the Champion's League group stage.
When it comes to goalkeepers, Tally Hall is rock solid behind the backline. Another 2011 all-star selection, Hall's 1.20 goals against average is among the best in MLS.
Hainault, Boniek Garcia, Taylor, and Je-Vaughn Watson spent the week on duty with their respective national teams. All four returned to Houston in time for this match.
Midfielder Giles Barnes is recovering from injury and should be available for the Dynamo in time for this game.
Boswell is one yellow card away from an automatic suspension. He will miss the season finale if he picks up a card in this matchup.
The Sept. 23 win at PPL Park ended the Union's three game losing streak against Houston. That Dynamo streak began last November with back-to-back playoff wins over Philadelphia.
Contact Kevin Kinkead at email@example.com. Follow Kevin on Twitter @PhilUnionKevinK