While both sides sit outside the playoff places, a win here could hand them a fighting chance in the qualifying race heading into the business end of the regular season.
Match preview
Chicago Fire looked set to mount a late push for a playoff spot when they fought back from two goals down to salvage a 2-2 draw against New York City FC in their first outing after Leagues Cup action on August 25.
However, Frank Klopas's men suffered a fresh setback last Sunday as they fell to a 4-1 defeat against a rampant Inter Miami when the two sides squared off at Soldier Field.
After a brace from Luis Suarez and Tobias Salquist's 25th-minute own goal put Inter Miami in a commanding lead, Georgios Koutsias pulled one back for the hosts in the 82nd minute, but Robert Taylor netted in the 93rd minute to retire the Heron's three-goal advantage.
Chicago Fire have now gone five consecutive games without a win across all competitions, picking up one draw and losing four, including back-to-back defeats against Sporting Kansas City and Toluca in the Leagues Cup, when they finished rock-bottom in Group D.
With 26 points from 27 matches, the Men in Red are currently 14th in the Eastern Conference standings, level on points with New England Revolution and Nashville in the bottom three and 11 points off the seventh-placed Orlando City.
While finishing in the guaranteed playoff places may be out of reach for Chicago Fire, they will have their sights on securing a spot in the wild-card round as they sit five points behind Atlanta United in ninth place with seven games to go.
DC United, on the other hand, picked up a huge result in their push for a post-season playoff spot as they secured a 3-1 victory over Toronto FC at BMO Field last Sunday.
With nothing to separate the sides heading into the final quarter of an hour, substitutes Martin Rodriguez, Dominique Badji and Gabriel Pirani all hit the target to inspire the visitors to all three points, with Deandre Kerr pulling one back for Toronto.
Prior to that, DC United were on a run of two consecutive defeats, losing 2/1 against Mexican outfit Mazatlan in the Leagues Cup round of 32 on August 10, two weeks before losing 4-3 against Dallas on their return to league action.
With last weekend's result, Troy Lesesne's men have now picked up three wins from four games in the MLS, a run which has rekindled their playoff dreams, having managed just three points from 11 matches preceding this run.
While victory on Saturday could see DC United move into ninth place and within five points of guaranteed top-seven places, they have failed to win any of their last nine visits to Soldier Field, losing three and claiming six draws since a 1-0 victory in June 2015.
Chicago Fire Major League Soccer form:
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D
W
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D
L
Chicago Fire form (all competitions):
W
L
L
L
D
L
DC United Major League Soccer form:
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L
W
W
L
W
DC United form (all competitions):
L
W
W
L
L
W
Team News
Chicago Fire will take to the pitch without the services of veteran defender Rafael Czichos, who is suspended after crossing the yellow card threshold with his booking against Inter Miami on Sunday.
On the injury front, Klopas will be unable to name the American duo of 26-year-old Mauricio Pineda and defender Chase Gasper, who have been ruled out through leg issues.
Ariel Lassiter, who has three goals and five assists in the league, is currently on duty with the Costa Rican national team while Koutsias has been named in the Greece Under-21 squad.
DC United, meanwhile, will have to cope without several key players down the spine of the team as David Schnegg (calf) Matai Akinmboni (ankle) and Conner Antley (knee) are all recuperating from injuries.
American forward Jackson Hopkins has been out of action since early August through an ankle problem while Russell Canouse continues his lengthy spell on the sidelines.
Boris Enow has been named in the Cameroon squad for September's Africa Cup of Nations qualifiers, while Aaron Herrera and Matti Peltola are on duty for Guatemala and Finland respectively.
Christian Benteke had an uncharacteristically quiet game against Toronto last time out and the Belgian striker, who has 17 league goals this season, will aim to return to the scoresheet this weekend.
Chicago Fire possible starting lineup:
Brady; Souquet, Salquist, Teran; Mueller, Navarro, Gimenez, Gutman; Haile-Selassie, Cuypers, Gutierrez
DC United possible starting lineup:
Bono; Tubbs, Bartlett, Mcvey, Santos; Stroud, Klich, Pirani, Dajome; Benteke, Ku-DiPietro
We say: Chicago Fire 2-2 DC United
Given the stakes of the game, we expect a thrilling contest at Soldier Field as both Chicago Fire and DC United aim to secure post-season football. While the Men in Red have struggled for results of late, they boast a solid home record against Lesesne's men and we predict they will do just enough to force a share of the spoils.