Craig Mitchelldyer/Portland Timbers

Coming off of a six-point homestand and playing their best soccer since March, the revitalized Portland Timbers face the ultimate test tonight: A trip north to CenturyLink Field to square off against Seattle's Western Conference-leading Sounders (6:30 p.m., TV on Fox Sports 1).

Portland is without a win against Seattle this year, and winless all-time in regular season games in the Emerald City. A victory tonight would send the Timbers to the top of the Western Conference, clinch the Cascadia Cup, and send a message that Portland is back in the MLS Cup conversation.

The History

It's been one frustrating year for the Timbers against the Sounders.

Portland dominated the first meeting of the year, in Seattle in May, but couldn't find the net. A Christian Roldan header — scored off a corner kick in the game's fourth minute — stood up as the difference.

The teams next squared off in the U.S. Open Cup, when a mostly T2 side was knocked 2-1 by a mostly S2 Seattle team at Starfire. But it was the last meeting, at Providence Park in June, that was the most bitter for the Timbers.

Seattle took the lead that night early, but Portland came storming back. Brad Evans was sent off for taking down Darlington Nagbe in the box, Fanendo Adi converted the penalty for 1-1, and then, just before halftime, a thunderbolt of a header from Dairon Asprilla gave the Timbers the lead.

It was a lead that — a man up — they never should have relinquished. But the Timbers' attack slowed in the second half, and Seattle stuck around until Clint Dempsey, off the bench, planted a header past Jake Gleeson to tie the game in its 94th minute.

As if that wasn't bad enough, Amobi Okugo — the Timber marking Dempsey — sprained his MCL on the play and only just returned to the team's matchday roster on Wednesday night.

The Tactics

The Timbers are still without the trio of Liam Ridgewell, Fanendo Adi, and Jake Gleeson — the former two players having injured themselves against LA at the beginning of the month, the latter a week later in Toronto.

The good news, to the tremendous relief of everyone who saw him lying collapsed on the ground at the end of the Timbers' win over Colorado, is that Dairon Asprilla is healthy. Asprilla was had thrown up game on Wednesday night, and was battling the flu, but he trained on Friday, and will be available tonight.

One other absence for the Timbers will be David Guzman, who, of course, picked up a yellow card against the Rapids and will be suspended. Caleb Porter could slide Darlington Nagbe back into central midfield in Guzman's place, but that move would run a significant defensive risk.

Craig Mitchelldyer/Portland Timbers

Porter trusts Lawrence Olum, for better or worse, and it seems most probable that Olum will get the nod at his natural holding midfield position with Larrys Mabiala coming back into back into the team after serving a suspension of his own to partner Roy Miller in central defense.

Up top, Fanendo Adi is a huge, huge miss. Not does Adi have a tremendous record against the Sounders, but his backups have been underwhelming in his absence.

Porter gave another start to his former Akron charge Darren Mattocks against Colorado, and while Mattocks was generally okay, he has zero feel for how to play as a single striker. Jeremy Ebobisse, meanwhile, plays that position well but got worn down physically in his start against the Red Bulls.

By most every measure, Ebobisse — who at the very least will make the right runs and give the Timbers' attack the right shape — should start. But Porter has faith in Mattocks, and might be concerned about Ebobisse's physical readiness against the likes of Chad Marshall and Roman Torres.

Seattle, unlike Portland, opted to rest several of their regulars — including Osvaldo Alonso and Clint Dempsey — in their 1-1 Wednesday night draw in Vancouver. Dempsey, though he came off the bench to great effect when these teams met in Portland in June, is in line to start.

The main question for Sounders manager Brian Schmetzer is whether he'll start Alonso and Gustav Svensson in central midfield with Roldan on the wing — a very conservative look — or line Svensson up in defense, pull Roldan into central midfield, and add another player to his attack.

Porter said in his press conference on Friday that he hopes this will be an open game, and Portland should come to attack. They have nothing to lose in this game, and they've played the better soccer in this series this year. They haven't been clinical enough to get the results.

The Lineup

1 - Attinella
5 - Vytas
7 - Miller
33 - Mabiala
16 - Valentin
13 - Olum
21 - Chara
6 - Nagbe
8 - Valeri (C)
10 - Blanco
17 - Ebobisse

The Pick

There are plenty of reasons to like the Timbers in this game. They're playing well and they're due — both for a positive result against Seattle this year, and for a win at CenturyLink. But it's hard to trust the Timbers' defense on any night, and the Sounders don't have just an ordinary attack. Seattle wins again, 2-1.