The Philadelphia Union need a victory Saturday at home to keep alive their postseason chances.
Playoff-bound Sporting Kansas City needs a win to maintain hopes of winning the Supporters' Shield.
Both teams will likely be looking to attack in their third meeting after splitting the first two with each winning on the road.
Philadelphia (12-11-10) must win or it will be eliminated. The Union then need to get favorable results from Sunday's games to move past Houston and New England for what would be the fifth and final playoff spot in the East since they cannot win tiebreakers with third-place Montreal or fourth-place Chicago.
"We need a little help from people on Sunday but we have to take care of business on Saturday, we have to get three points, we have to beat a very good Sporting Kansas City team," coach John Hackworth said.
Kansas City (16-10-7) must win and hope that New York loses at home Sunday to Chicago in order to gain the No. 1 seed in the East as well as the Supporters' Shield.
Hackworth faces a challenge since he will have to replace captain Brian Carroll, who has started 59 straight games but is suspended for this one due to yellow-card accumulation. Hackworth has not indicated how he will alter his lineup.
The coach has made his team aware that it will have to go on the attack early since a victory is necessary.
"We certainly understand where we are and what we have to do," Hackworth said. "That means we can't leave it late, if you will, which means we're going to have to take a little more risk."
Philadelphia forward Sebastien Le Toux is tied for the league lead with 12 assists, although he sat out last Saturday's 2-1 loss at Montreal with foot problems after coming off the bench in the previous three games due to the same issue. Le Toux's status is unclear.
Sporting Kansas City had the added distraction this week of a CONCACAF Champions League match with Honduran club CD Olimpia. The scoreless result Wednesday was enough for Kansas City to advance to the quarterfinals.
"Three points would have been great for the seeding, but the way we're looking at it is that we advanced and that was one of our goals at the beginning of this season, so we're happy from that standpoint," defender Matt Besler said.
Goalkeeper Jimmy Nielsen is tied with Portland's Donovan Ricketts for the league lead with 13 clean sheets, including three straight during Kansas City's 2-0-1 run in MLS play. Nielsen, however, has yielded eight goals in his last five starts against the Union.
Philadelphia defender Sheanon Williams will become the first player in club history to play 100 MLS matches.
"The only way for us to even think about playoffs is winning the game," Williams said. "We'll definitely do our best but I guess gamble safely, which sounds stupid but you can't throw all caution to the wind and go down two goals, that's not going to help us. We have to do it smartly."