Fourteen teams are vying for this year’s MLS Cup, and the postseason features a single-elimination bracket, a first in the league’s 24-year history. The Sounders earned the No. 2 seed and will host seventh-seeded FC Dallas on Saturday at CenturyLink Field. Here’s a closer look at essential information to know heading into Seattle’s opening-round matchup: Tale of the season Seattle’s path to the playoffs wasn’t easy. Injuries, international call-ups and conceding 19 goals during a late-season stretch toyed with the Sounders’ standing in the Western Conference. The Sounders clinched the No. 2 seed with a 1-0 result against Minnesota United on Decision Day, meaning Seattle is guaranteed to be a host through the conference semifinals. MLS Cup Playoffs First round Game: Sounders vs. FC Dallas. When: 12:30 p.m. Saturday. Watch, listen: FS1, FOX Deportes (Spanish); 950 AM, 1360 AM (Spanish). FC Dallas was on a four-game winless streak — including a scoreless draw against Seattle — before a 6-0 outcome against Sporting Kansas City clinched its playoff berth on Decision Day. The club is making its fifth postseason appearance, but this is the first under coach Luchi Gonzales, who’s also making his pro coaching debut. Gonzales has the club taking…