In their first action in nearly two weeks, the Dynamo look to extend their unbeaten run to five while the Timbers try to add to their team-record six-game home unbeaten streak Friday night.
Houston (10-9-13) hasn't played since a 1-all draw with Chicago on Oct. 1, while Portland's last game was a 1-0 win in Vancouver on Oct. 2.
The Dynamo have gone 2-0-2 in their last four to stay in playoff position. The expansion Timbers are three points behind Houston and New York and can move into a tie with them for one of the final two wild-card spots Friday.
Portland (11-13-7) has three games remaining - one more than the Dynamo and Red Bulls - but will be playing its final home game of the season.
The Timbers are 9-4-3 at Jeld-Wen Field and 4-0-2 in the last six there. All of Portland's home games have been sellouts.
"There's a great energy, a positive energy, when we come out on the field (at Jeld-Wen), and I think that drives us forward," coach John Spencer told the league's website.
The Timbers are 1-4-2 in their last seven away from home, so this game provides an important opportunity for Portland to gain points before it visits D.C. on Wednesday and Real Salt Lake next Saturday.
The Dynamo are 1-6-9 on the road but defeated FC Dallas 1-0 in their most recent away game Sept. 24. Houston can clinch its fifth playoff berth in six seasons of existence with a pair of wins, but has a difficult matchup in its season finale against Los Angeles on Oct. 23.
"We have a game in Portland that will be a playoff atmosphere," midfielder Brad Davis said. "I think our playoffs start then in an amazing atmosphere on the road. I think we're going to see what our team is made of.
"Then we have a game with (Los Angeles) ... We need to get maximum points out of these games to put ourselves in a good spot."
Houston took its first matchup with Portland 2-1 on Aug. 14 as Adam Moffat and Brian Ching scored in the first half. Jack Jewsbury scored for Portland, but he hasn't found the back of the net in seven games.
Jewsbury, who is tied for the team lead with seven goals and has a team-best seven assists, was forced to sit out the win over Vancouver due to yellow-card accumulation. In his place, Kenny Cooper scored his third goal in four games.