In terms of the possible, this is likely the most important game the Sounders have scored all season. In terms of the probable however, it's significantly less crucial. That might seem counter-intuitive, but it's true; LA Galaxy are the odds-on favorite to win the Supporters Shield at this point but a win for either side will keep them close enough that there's still some doubt, especially on the off chance the Galaxy drop points against San Jose. A draw and an LA win means things are all but decided, while a loss for either side almost certainly means that any chance of leapfrogging the teams in front is out the window. But if you consider the most likely outcomes, no result is likely to have a huge impact on the final standings unless there is a major dip in form by one or more of the top three in the Western Conference. Colorado and Real Salt Lake are still within shouting distance, but Dallas and Seattle are more likely than not to end up second and third in the west, meaning they'll be each others first opponent in the playoffs.
But of course the possible is still vitally important, and since the Sounders are likely going to need to get past FC Dallas should they hope to make a run at the MLS Cup it would be an encouraging sign if they were able to steal a result at Pizza Hut Park. That's obviously not an especially easy task; Dallas has a pretty strong case as being the best team in MLS over the past two to three months. In 13 home games this season they've won 8 and lost only twice, the first in the second week of the season to San Jose (in the midst of a shockingly poor start) and the other coming in mid-June to a Sporting KC side that was at the time the hottest in MLS. In other words, three points would be a pretty big ask.
But while there's really no good time to face FC Dallas at Pizza Hut Park, the Sounders are likely catching them at the best possible moment. While both teams will go on short rest, the Sounders do have an extra day of rest and played at home Tuesday night rather than traveling to Mexico City for Wednesday's historic Dallas win. And while the Sounders started a fair number of first choice players, Dallas opted for an even stronger side at the punishing altitude and harsh environs of Mexico City. That means the Toros are either going to be at less than full fitness or fielding a less than full-strength side, and they'll also be without one of their most important players in defender George John who will miss the game due to a one-game red card suspension.
For Seattle's part, we'll probably something of a weakened side as well. The team's intentions against Monterrey on Tuesday night will be a major factor in the team selection, but Brad Evans and Jhon Kennedy Hurtado are both major question marks. Alvaro Fernandez played the entire game against Comunicaciones while Lamar Neagle made an unexpected early exit, meaning it's likely we'll see Neagle given the nod. Mauro Rosales should be good to go. The big question on everyone's mind is, as always, concerning the forwards; Mike Fucito earned a more extended run of games with his performance on Tuesday night, but it's unclear whether that run will begin tomorrow or at a later date (assuming it begins at all.) If Fucito does get the nod, it wouldn't be a surprise to see Fredy Montero on the bench (at least to start) meaning that one of Roger Levesque, Pat Noonan or Nate Jaqua may well be in the mix for at least one more game. If Fucito doesn't start, don't read too much into it; he hasn't gotten a whole lot of game time as of late and after going completely insane for 90 minutes on Tuesday night there might be some fitness concerns. Frankly given his track record, saving him for Monterrey might make a whole lot of sense.
Dallas is a very dangerous team and in many ways they're something of a more fully realized version of what the Sounders are hoping to become. But they're far from invincible, especially given the timing of this game. It's hard to imagine things getting out of hand in either direction; these are two very evenly matched teams with a whole lot at stake and the Sounders are never out of any game they can keep close. Even if this game ends up being largely inconsequential in terms of the final standings, it ought to be an absolute barn-burner.