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The Seattle Sounders have been one of the perennial success stories of Major League Soccer. Not only do they always lead the league in attendance and profitability estimates, but they've also never missed the playoffs. The Sounders have been synonymous with success.

But lately, their record on the field has been cause for concern. Halfway through the season, the Sounders face a crucial fork in the road: Either they can finally get their attack going or potentially face their worst-ever finish in MLS. For all the talent the Sounders have, the team never has been so low in the standings so late in the season, and, well, something's got to give.

With a huge rivalry match coming against the Portland Timbers on Sunday (3 p.m. ET, FOX), there would be no better time for the Sounders to turn a corner. Seattle, in second-last in the West, had their first excellent performance of the season on Wednesday, routing first-place FC Dallas 5-0. To be fair, FC Dallas did field a reserve team while their best attackers rested due to a grueling schedule, but it may not matter -- a 5-0 win may be the confidence boost the Sounders need going into Sunday.

The Sounders have little choice other than to try to force their latest win into the start of something, though. The Sounders are averaging just 1.11 points per game, fourth from the bottom in the 20-team league and worse than last year's bottom playoff team in the West. If they can't keep winning and they don't start a streak in Portland, their point deficit may become insurmountable sooner rather than later.

The marching orders for the Sounders are simple: score, score, score. Before their lopsided blowout on Wednesday, the Sounders were averaging just .8 goals per game, last in the West. In 2014, when Seattle finished first in their conference, they averaged nearly 2 goals. Last year, when they made the playoffs but weren't great, they averaged 1.3 goals. So, it's pretty easy to see why this year is going so poorly: their attack is anemic.

Figuring out why the Sounders can't score is slightly more complicated. It's not for lack of trying -- the Sounders are exactly halfway down the league list in shots taken. Going into Wednesday's match, which could prove to be an anomaly, the Sounders were converting around just 6 percent of their shots, the lowest conversation rate in MLS. The problem seems to be either that they aren't getting high-quality shots or they aren't finishing the good chances have -- or, probably, a bit of both.

The loss of forward Obafemi Martins right before the season started has proved to be devastating for the Sounders. In his three years, Martins linked up successfully with striker Clint Dempsey for one of the best attacking duos in the league. Without Martins' speed, creativity and finishing ability, the Sounders have been missing something. Jordan Morris is a promising young forward, but the rookie can't single-handedly make up for Seattle's deficiencies the way Martins could and Morris is still working on his finishing.

What could help the Sounders get more out of the likes of Morris and Dempsey is finding a central "No. 10" playmaker who can set up the attack and ensure quality chances. With so few goals and assists created, it appears no one in the final third is bearing the responsibility for creating chances and setting the tone of the attack. Bringing in someone to do that could force coach Sigi Schmid to rethink the team's current 4-3-3 formation -- but that might not be so bad, because we saw how well Dempsey responded to switching to a 4-4-2 of sorts in Copa America.

Here's the good news: Overseas reports have suggested the Sounders may be close to signing such a playmaker in this summer transfer window. Uruguay's Nicolas Lodeiro has been rumored, as well as Paraguay's Oscar Romero. On top of it, Morris seems to be slowly but surely starting to find his form after seven goals in 17 games. It looks like things could start falling into place, but it needs to happen soon.

The implications for the Sounders' season certainly add some bite to Sunday's matchup, the biggest rivalry MLS has to offer. For Portland, they hardly want to be the team that allowed the Sounders to turn things around and the Timbers, sitting just outside of playoff position, need the points pretty badly themselves. For the reigning MLS Cup champions, it's been a bumpy year with a constant stream of bad-luck injuries that meant the Timbers' best XI seldom has actually played together. For all of Seattle's struggles, there's no reason they can't beat the Timbers.

If the Sounders can't muster up some sort of goal-scoring effort against their most bitter rival, the season will slip further away and there may not be much hope left in Seattle.

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