After drawing their opening games, both sides are looking to end their two-game losing streaks heading into this match.
The Fire have been slow out of the gates, once again failing to earn more than a point in their first three games, which is exactly how this team started their 2020 campaign.
Raphael Wicky and his team will be happy to return to Soldier Field as they have struggled to get three points away from home.
If you take away the "MLS is Back" tournament last season, Chicago have not won on the road since their regular-season finale in 2019, when they beat Orlando 5-2.
While they have had more success playing in the windy city, they have not won at Soldier Field in their last four regular-season games, including a 2-2 draw in their opening match against the New England Revolution.
However, the last time they hosted Philadelphia, they did come away with a 2-0 win back in 2019 in a match played at SeatGeek Stadium in Bridgeview, Illinois.
It may be a surprise to see the Union without a win in three games, but it is not unusual given how they have begun their past two campaigns in MLS.
In 2019 and 2020, they were winless in their three opening games but recovered each time, finishing first overall in the 2020 regular season.
So far in 2021, we have seen two very different Philly teams who have achieved very different results in MLS and the CONCACAF Champions League.
Jim Curtin will hope to see the same team that look unbeatable in the Champions League show up again on Saturday.
The Union advanced to the semi-finals of that competition on Tuesday, beating Atlanta United 4-1 on aggregate, and are unbeaten in their last four Champions League matches, scoring nine goals and conceding only one.
It will be a while before Fire fans see winger Stanislav Ivanov, who will not be available until this summer after undergoing knee surgery late last month.
Left-back Miguel Navarro could miss his third straight game with an ankle injury.
Striker Elliot Collier is a possibility to return from an ankle injury.
Polish striker Kacper Przybylko will look for his first goal of the regular season on Saturday, having scored five times in the Champions League and leading this team in scoring over their past two MLS campaigns.
Chicago Fire possible starting lineup:
Shuttleworth; Bornstein, Calvo, Kappelhof, Sekulic; Pineda, Gimenez; Medran, Stojanovic, Frankowski; Beric
Philadelphia Union possible starting lineup:
Blake; Mbaizo, Glesnes, Elliot, Wagner; Sullivan, Bedoya, Monteiro, Fontana; Przybylko, Santos
We say: Chicago Fire 0-2 Philadelphia Union
These teams may be level on points so far this season, but the Union have shown signs they can turn things around, especially with their strong performances in the Champions League.