The hosts played out a goalless draw with the San Jose Earthquakes last time out, while the visitors suffered a 2-1 defeat against the Columbus Crew.
Match preview
It would not be unfair to say that Portland have experienced a wildly inconsistent campaign up to now, as they head into Wednesday's clash with a record of five wins, six draws and seven losses.
That said, the Timbers appear to have established a sense of stability in recent weeks, notching a three-game unbeaten run thanks to a 1-0 victory over FC Dallas and goalless draws with the Seattle Sounders and San Jose Earthquakes.
Not only have Giovanni Savarese's men avoided defeat in each of their last three matches, but they have also kept three consecutive clean sheets, conceding just two goals across their previous six league outings for good measure.
Better still, Portland have lost only two of their last nine MLS outings, picking up three wins and four draws along the way, so the Oregon outfit are certainly moving in the right direction.
Having suffered a solitary defeat in their previous six home league games - securing victories over the Seattle Sounders, Vancouver Whitecaps and FC Dallas in the process - the Timbers will be confident of heaping more misery on Chicago Fire.
Following last week's defeat to the Columbus Crew, Chicago enter Wednesday's showdown on a six-game winless run in the league, having recorded three draws and three losses since their last victory.
When you look at the bigger picture, the Fire have managed to win just one of their previous 11 MLS encounters, recording five draws and five defeats to remain second from bottom in the Eastern Conference - two points above Inter Miami.
Ezra Hendrickson parted ways with the club on May 8 after overseeing two wins, five draws and three losses at the start of the season, leaving Frank Klopas to take the reins on an interim basis.
However, the new manager has so far failed to turn things around, taking six points from a possible 21 since his arrival, with the Fire's US Open Cup journey ending in the quarter-finals due to a 4-1 thrashing at the hands of Houston Dynamo.
It is also worth noting that Chicago have enjoyed very little success on the road this year, winning only one of their eight away league outings while suffering five defeats, so they will struggle to spark a revival at Providence Park.
Portland Timbers Major League Soccer form:
D
L
L
D
W
D
Chicago Fire Major League Soccer form:
L
D
D
D
L
L
Chicago Fire form (all competitions):
D
D
D
L
L
L
Team News
The Timbers have multiple injury absentees at the moment, with Felipe Mora (knee), Yimmi Chara (hamstring), David Ayala (knee), Eryk Williamson (knee) and Juan David Mosquera on the sidelines.
There are also question marks over the fitness of Pablo Bonilla, who has not seen any first-team action since March after picking up a hamstring injury.
Franck Boli and Evander look set to continue in attack for Portland, while Zac McGraw and Dario Zuparic are expected to resume their centre-back partnership on Wednesday.
As for Chicago, they will be without the injured duo of Carlos Teran (leg) and Chris Mueller (leg) for the trip to Oregon, although Miguel Navarro is back in action after missing the defeat to FC Cincinnati earlier this month.
Frank Klopas is expected to stick with a 3-4-2-1 formation, meaning that former Liverpool, Bayern Munich and Inter Milan star Xherdan Shaqiri will continue to operate behind lone striker Kei Kamara.
At the opposite end of the pitch, Arnaud Souquet, Mauricio Pineda and Rafael Czichos will likely operate in defence, with Maren Haile-Selassie and Miguel Navarro occupying the wing-back roles.
Portland Timbers possible starting lineup:
Bingham; Miller, Zuparic, McGraw, Bravo; Moreno, Paredes, Chara, Aprilla; Evander, Boli
Chicago Fire possible starting lineup:
Richey; Souquet, Pineda, Czichos; Haile-Selassie, Gimenez, Navarro, Navarro; Shaqiri, Gutierrez, Kamara
We say: Portland Timbers 2-0 Chicago Fire
Having avoided defeat in each of their previous three matches - keeping three clean sheets in the process - the Timbers are expected to make light work of Chicago, who have failed to win any of their last six league outings.
How to watch
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