Thanks to Drew's work this week on playoff scenarios, enumerating many of the scenarios that would lead to a potential repeat of this is now a simpler task. One interesting note I discovered working through these scenarios: there is only one scenario related to Seattle and Portland in which today's goal differential might matter. If San Jose ties, and Seattle loses by at least three goals, then San Jose could take Seattle's seed. Otherwise, no goal differential today, no matter how lopsided, can determine the fate of Seattle or Portland.*

Here are the results that would lead to a Timbers-Sounders one-game playoff.

Portland hosts Seattle: 20% Probability

Portland is currently sitting fourth and Seattle is in fifth, which would, of course, lead to Portland hosting a play-in game midweek. There is no way that Sporting and Vancouver or Sporting and LA somehow switch places and leave Portland and Seattle in fourth and fifth, so this first-round scenario only holds if everyone just stays where they are (relative to the Timbers and Sounders, that is). The probability of this is 13%, and an example from Drew's spreadsheet is below.