MLS Playoff Preview: Conference semifinals promise intrigue

The calculus changes as the conference semifinals beckon. These two-legged ties fall under a broader remit. They require careful management and keen awareness of the full picture. It is not just about one day. It is about shifting into position to emerge victorious after home and away legs.

It is a principle worth keeping in mind as the conference semifinals commence on Sunday. The outcomes of these first legs matter a great deal, but they also require context with a wider lens. There are away goals to contemplate and deficits to ponder. At this point, it is about maneuvering into the proper position and then waiting to finish off the job next weekend.

Eastern Conference: (4) D.C. United -- (1) New York Red Bulls, 3:00p.m. ET (ESPN)

United mustered a display filled with character and resolve to dispatch New England in midweek. Those efforts highlighted the mental strength of this veteran group, but they also extracted a significant cost in the process. Chris Pontius is expected to miss this match at RFK Stadium with a hamstring injury, while Bobby Boswell is sidelined through suspension for his off-the-ball incident with Revolution forward Juan Agudelo. Boswell’s absence proves particularly troublesome with Bradley Wright-Phillips poised to exploit any gaps in the United defense (Steven Birnbaum and Kofi Opare are expected to partner in Boswell's absence).

Those personnel issues leave United somewhat exposed ahead of this renewal of hostilities with the Red Bulls. New York presents an awkward matchup given the Red Bulls’ penchant for pressing high and United's generally lack of facility on the ball. United must navigate through those difficulties in possession, track Lloyd Sam intently (three goals in three meetings this season) and try to punish the Red Bulls’ high line with direct runs in the channels by Fabian Espindola and Chris Rolfe. Espindola and Rolfe must produce here to visit Red Bull Arena next Sunday with a chance to advance.

Western Conference: (3) Portland Timbers -- (2) Vancouver Whitecaps, 5:00p.m. ET (ESPN)

The challenges in this particular game are all too familiar for the Timbers. Sporting Kansas City spent long stretches soaking up pressure and waiting for the right time to counter on Thursday. Vancouver promises to adopt a similar approach in a bid to grind out a result at Providence Park.

Portland must figure out a way to pull apart the Whitecaps’ compact, well-drilled shape. There is a need to exploit the fullback areas and press the adventurous Whitecaps wingers into defensive duties first and foremost. Those are necessary steps given Vancouver’s strength in central midfield -- even with influential schemer Pedro Morales hobbled and his vital diagonals stripped out of the Whitecaps' counterattacking arsenal -- and the desire to place Darlington Nagbe and Diego Valeri in the right areas. The primary caveat for the Timbers: They must maintain the proper balance to ensure the fleet Whitecaps do not hit them on the break and snatch an away goal or two ahead of the return leg at B.C. Place next Sunday.

Eastern Conference: (3) Montréal Impact -- (2) Columbus Crew SC, 7:00p.m. ET (FS1, FOX Sports GO, FOX Deportes)

Columbus burst into the postseason with a comprehensive 5-0 victory at D.C. United. That triumph last weekend earned Crew SC an entire week off and paved the way for this difficult trip to Stade Saputo. The impending return of Federico Higuain and Kei Kamara from one-match suspension offered another boost to those preparations.

Western Conference: (4) Seattle Sounders -- (1) FC Dallas, 9:30p.m. ET (FS1, FOX Sports GO, FOX Deportes)

These two sides met at this stage a year ago and spent most of the tie flailing around without much success. Seattle eventually edged through on away goals after a 1-1 draw in the first leg. It is a result worth noting as FC Dallas prepares for this fraught trip to CenturyLink Field.

Seattle must figure out how to balance its intentions and maintain the proper shape. FCD punishes teams that pursue the game too vigorously with its pace on the break and its willingness to rely on Fabian Castillo and Mauro Diaz to orchestrate in the open field.