The Supporters' Shield winner heads to Frisco following a first round bye while FC Dallas gets ready for coming off a quick turnaround in Wednesday's 2-1 win over Vancouver.
For the most part, manager Sigi Schmid will produce a full, healthy lineup in the Sounders' first playoff game of the season.
Questionable: Damian Low (L hip surgery)
Out: Kevin Parsemain (ACL tear), Andy Rose (R knee bone bruise)
Seattle will style a 4-1-3-2 formation with one man playing in front of the back line behind the midfield.
GK: Stefan Frei; LB: Leo Gonzalez; CB: Zach Scott, Chad Marshall; RB: DeAndre Yedlin; DCM: Osvaldo Alonso; LM: Lamar Neagle; CM: Gonzalo Pineda; RM: Brad Evans: F: Obafemi Martins, Clint Dempsey
Fabian Castillo vs. Yedlin - Two young, speedy athletes going at each other will be a huge factor in Sunday's semifinal. Castillo has been so use to blazing past defenders on his left side, however, the USMNT standout will be looking to have none of the Columbian in his flank. It'll be interesting how FCD chooses to deal with Yedlin containing and trying to cut off FCD's left side.
Keys to Win
Disciplined defense. Seattle, of course, has one of the strongest offenses in the league. With Martins and Dempsey upfront for the Sounders, anything can happen to cause problems to FCD's back line. Matt Hedges has to control Walker Zimmerman and his outside backs and keep the Sounders from getting behind on their runs. If Hedges wants to make his run for USMNT, he needs to be able to defend the USMNT star forward.
Strong 90 minutes. FCD did a good job possessing the ball in the first half of Wednesday's match, but a lot of the second half looked more in Whitecaps' favor. If FCD wants to take this first game against Seattle, the Hoops cannot slack off for an intervals of time. The second FCD loses the tone of the game will be the second Seattle capitalizes.
Pass to Perez. Blas Perez was relatively quiet in the Knock Out Round against Vancouver. He had no shots in Wednesday's contest, meaning no shots on a goal. If he's going to be a valuable striker, he has to see strikes on goal. Whether that is finding his head with early crosses or playing a nice feed to him inside the box, something has to happen. Perez has to be a part of play Sunday.