The Union can draw even with Montreal atop the Eastern Conference with a win over the resurgent Impact.
The Impact (12-7-5), who had won one of their past eight league matches before those two straight wins, hold just a three-point lead over the Union (10-8-8). And Montreal is only five points up on the Houston Dynamo, who are on the outside looking in at a playoff berth in the congested conference.
Philadelphia is without suspended center back Amobi Okugo, while fullback Ray Gaddis and midfielder Keon Daniel are both questionable with ankle injuries. Right back Sheanon Williams is likely to tuck inside and partner with Jeff Parke, giving a makeshift duo the unenviable task of tracking MLS leading scorer Marco Di Vaio (15 goals).
Although Montreal coach Marco Schallibaum is still suspended following an altercation with D.C. United boss Ben Olsen two weeks ago, the Impact will be feeling confident tactically after their revised 4-2-3-1 formation clicked on all cylinders last weekend in a 5-0 win over Houston.