The visitors, meanwhile, are currently two points adrift of the playoffs, and they will be hoping that a win against Portland will move them into the top seven of the Western Conference.
Match preview
Portland have find it tough to bounce back from last season's MLS Cup defeat, with their 17 matches this term yielding 19 points, leaving them in 11th place in the Western Conference.
Rather than defeats, a failure to convert draws into victories has hampered Portland's progress this term.
The Timbers have drawn seven games this season - more than any side in the Western Conference - but they will enter Wednesday's contest in a confident mood after beating Colorado Rapids 3-0 at the weekend.
Sebastian Blanco grabbed the opener in first half stoppage time before Jaroslaw Niezgoda netted a quick-fire brace after the restart to help Portland end a four-game winless run.
Giovanni Savarese's will now be looking to clinch consecutive victories, and they will be confident of doing so after winning their last four home meetings against Houston Dynamo.
Houston sit two points clear of their hosts, but rather than looking over their shoulder, they will be focused upon the two-point gap that separates them from the playoffs.
The Dynamo began the season in style, enjoying a four-game unbeaten run, but the momentum gained from their impressive start has dissipated.
While it took them just four matches to rack up three victories, it has taken them ten more games to double that win tally.
The latest victory occurred at the weekend, with Houston netting two first half goals to condemn Chicago Fire to a 2-0 defeat.
Thorleifur Ulfarsson grabbed his second goal of the season to give his side the lead in the 23rd minute before Darwin Quintero struck in first half stoppage time, ensuring Houston head to Portland in a confident mood.
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Team News
Portland are still without Diego Gutierrez, who remains sidelined with a foot injury, while Cristhian Paredes is a doubt after being forced off in the first half against Colorado.
Larrys Mabiala is available for Wednesday's contest after serving a one-match suspension, but the defender may have to settle for a place on the bench, with Savarese expected to keep changes to a minimum.
After scoring a brace at the weekend, Niezgoda will keep his place in the frontline, and the 27-year-old will be looking to add to the five goals he has scored this season.
As for Houston, they are expected to have a full squad available for Wednesday's away trip.
Following Saturday's 2-0 win over Chicago, the visitors avoid making too many changes to a winning lineup, although Paulo Nagamura may be tempted to bring Tim Parker back into the starting XI.
Sebastian Ferreira will continue to lead the line for his side, and he will be hoping to continue his fine form after scoring six goals in his last nine appearances in the MLS.
Portland Timbers possible starting lineup:
Ivacic; Van Rankin, Zuparic, Tuiloma, Bravo; D. Chara, Williamson; Moreno, Blanco, Y. Chara; Niezgoda
Houston Dynamo possible starting lineup:
Clark; Zeca, Parker, Hadebe, Lundqvist; Ceren, Vera; Rodriguez, Quintero, Ulfarsson; Ferreira