Due mostly to geography, there Seattle Mariners and Seahawks don't really have a single main rival that gets fans' blood boiling.
It's likely Seattle Sounders FC won't either, until the league gets around to expaning into Portland or Vancouver.
So in this expansion season, it's likely the San Jose Earthquakes will have to do.
The Earthquakes are the nearest team geographically, if not exactly neighbors. And the Sounders and Earthquakes are the only MLS teams will names and historys -- and yes, rivalries -- dating back to the North American Soccer League.
One problem for the Sounders, is that while the Earthquake may start of Seattle's top rival, San Jose is more focused on the in-state, high-glamour LA Galaxy.
Still, the teams will meet on the pitch for the first time next week, and then they'll cross paths three times during the regular season -- two in Seattle.
So, after Earthquakes training today in Santa Clara, Calif., I talked to Quakes coach Frank Yallop about his team's new rival to the north.
"I think if you look at Seattle, Vancouver and San Jose in the old days, they were great rivals," he said. "I think this will get going. We've got a great rivalry with LA, obviously. But I think that Seattle now, we can't wait for our first game against them, and I'm sure they're thinking the same. It's good, I like when it's a close neighbor when there's some bragging rights there, and I'm sure Seattle's thinking the same. You know they want to put one over on us, and I think it's going to be a healthy rivalry there."