WHEN THE UNION players walk through the tunnel and onto the PPL Park pitch tomorrow night, it could be the start of their last meaningful game of this up-and-down season.

It's up to them to make sure their following two weekends carry the same importance as this one.

There's no way around it - the Union (9-10-12) needs three points against the Columbus Crew (11-10-10) to keep its already slim postseason hopes alive. A loss and a New York Red Bulls win against Toronto FC tomorrow would mathematically eliminate the club from contention.

As it stands now, the Union has a 12.4 percent chance at qualifying for the postseason, according to the website, Sports Clubs Stats. Houston's 1-0 win over Toronto on Wednesday helped Philadelphia's odds because Toronto is one spot ahead in the standings, but it also made it so the Dynamo tied the Union in the standings, with 39 points.

"There's no denying the window of opportunity is closing," Union interim manager Jim Curtin said after the team's training session yesterday. "There's no room for 'Oh, if we get it right next game.' That's done. That's out the window. They feel that. Coaches feel that. Players feel that. And the good ones rise to the occasion."

After sitting out last Thursday's disappointing draw with Chicago, the Union's top two goal scorers, Sebastien Le Toux and Conor Casey, are expected back pitch tomorrow. Le Toux said after training yesterday that his right ankle felt 80 to 85 percent. Casey, coming back from knee tendinitis, yesterday trained for the first time in about a week and also said he hopes to play.

The Union sorely missed the presence of those two veterans last week. Le Toux has scored a team-leading 12 goals this season, four more than Casey, the teammate with the next-best total. They have combined for five game-winning goals this year.

With Le Toux, Casey and defender Sheanon Williams (quadriceps) likely back, the Union expected to field a full-strength lineup for this crucial game. But playmaking midfielder Cristian Maidana missed training yesterday with flu-like symptoms and is questionable to play. Center back Ethan White isn't a sure thing, either, as he's now dealing with a back issue, according to Curtin.

This will be the Union and Crew's second meeting of the season, but first in nearly 7 months. The teams played the third week of the season, so long ago that the 2-1 Columbus win won't play much into how either squad game-plans for tomorrow.

One similarity will be the player tending the goal for the Union. Zac MacMath will make his 100th career MLS start and perhaps his last of this season. Rais M'Bolhi, the goat of last week's Chicago game, is fulfilling a call-up to the Algerian national team in the African Cup of Nations. He is expected back for the season's final two games.

MacMath, who has performed well in his 26 starts this year, hasn't played since the Lamar Hunt U.S. Open Cup championship match on Sept. 16. Curtin said MacMath had a "great week" in training and added, "I can't say enough about how much of a professional he's been."

The fact that this could be his last appearance of 2014 doesn't faze the 23-year-old keeper.

"I don't need more motivation to go out there and play my best. This could be my last game [or] it could be one of many games that I continue to play this year," MacMath said. "So I'm just going to go out there and give my best and hope that it gets the team a win."

Free kicks

The kickoff time for the Union's Oct. 26 regular-season finale at Columbus was moved up an hour to 4 p.m., Major League Soccer announced this week . . . The Union is unbeaten in its last nine home games . . . Tomorrow is Breast Cancer Awareness night at PPL Park.