The Sounders will be playing the Houston Dynamo for the Western Conference championship of Major League Soccer.
Houston advanced in the MLS playoffs with a 2-1 road victory over the top-seeded Portland Timbers on Sunday.
Defending MLS Cup champion Seattle and Houston will meet in a home-and-home, total-goals series that starts Nov. 21 in Houston.
Sounders (2) vs. Houston (4)
Leg 1 at Houston: Nov. 21, 7 p.m., FS1
Leg 2 at Seattle: Nov. 30, 7:30 p.m., ESPN
Toronto (1) vs. Columbus (5)
Leg 1 at Columbus: Nov.