Seattle has two sets of rivalries. There's Cascadia and that got on national television because of the fanbases and then there's a group of three "Cup Contenders" - RSL, LA and the Sounders. Those are the two teams that Seattle has played the most due to two two-leg playoff matches. They have comparable all competitions records. The other two have both won an MLS Cup since 2009. Both are in the CCL.
These are rivalries based not on region but instead the pressure of meaningful games year after year. On the field, play is just as fierce in these matches. Two high quality teams? Decent rivalry? Contesting the #2 spot in the West? NHL lockout?
NBCSportsNet picked up the game nationally, but is using Ross Fletcher and Kasey Keller as their talent. The game remains available on KONG and Root Sports per their usual contracts. This also means an NBC hype video, because who wouldn't want more hype videos?