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In search of its fourth straight league win, Seattle Sounders FC can solidify second place in Major League Soccer with a result against the Philadelphia Union on Saturday.

By taking just a point from Saturday's tilt against the Union, the Sounders can guarantee that they will finished no worse than runners-up in the 2011 season.

But a win would see Seattle, which trails the Los Angeles Galaxy in the hunt for the MLS Supporters' Shield by seven points, close the gap on the league- leaders with two games remaining.

The Sounders have already claimed silverware this season, wrapping up the U.S. Open Cup with a 2-0 victory over the Chicago Fire on Tuesday. Fredy Montero and Osvaldo Alonso provided second-half goals to secure Seattle's third straight Open Cup title.

With a playoff berth and a trophy already under their belts, and with two MLS games and a CONCACAF group stage match left on the schedule, it is unclear which players Sounders head coach Sigi Schmid will put on the field on Saturday.

One Sounders star certain to miss the clash is Tuesday's hero, as Montero is unavailable due to yellow card accumulation.

The Union, meanwhile, have several question marks of their own with regard to player personnel.

Goalkeeper Zac MacMath is listed as questionable with an ankle sprain, and with third-string 'keeper Thorne Holder nursing a concussion, Philadelphia may have to resort to starting Chase Harrison, who was signed following Faryd Mondragon's broken finger.

"You just have to pay your dues and when the opportunity comes, hopefully you can make the most of it," Harrison said. "You have to be ready."

Philadelphia is unbeaten in its last six regular season matches, posting a 2-0-4 record over that stretch.

"Regardless if we got the win or not, I think the last six games were very good," Union head coach Peter Nowak said. "And we're still in a position to control our own destiny with three games to go."

The Union are tied with the Columbus Crew for second place in the Eastern Conference with 44 points apiece, trailing Sporting Kansas City by just a point.

In their last meeting, Philadelphia and Seattle played to a 1-1 draw at PPL Park in April. Carlos Ruiz gave the Union the lead, but Alvaro Fernandez stole a point for the SOunders with a stoppage time goal.