The visitors, meanwhile, are competing in their first European campaign since the 1964-65 Inter-Cities Fairs Cup after finishing second in the Belgian First Division last season.
Match preview
After being eliminated in the Europa Conference League group stage, Union Berlin are looking for an improvement in European competition this time around.
They swap the third tier UEFA competition for the Europa League this term, as a result of finishing the 2021-22 Bundesliga season in fifth place.
Urs Fischer's side enter the group stage full of confidence after starting the new season with a six-game unbeaten run in all competitions.
The current fourth-placed side in the Bundesliga held the German champions Bayern Munich to a 1-1 draw at the weekend, which will give them belief that they can compete against high-quality opposition ahead of their Europa League campaign.
Although they were only able to win two of their six Europa Conference League group games last term, they enter Thursday's contest looking to extend their unbeaten competitive home run to 11 games.
Meanwhile, Union SG earned themselves a place in Champions League qualifying after going close to winning the Belgian First Division title last season.
Despite beating Rangers 2-0 in the home leg of their third-round qualifying tie, a disappointing 3-0 defeat at Ibrox in the second leg ensured Union SG dropped down to the Europa League group stage.
Playing in their first European campaign in 58 years, Union SG will be hoping they have the quality to finish in the top two of a group that contains Malmo, Braga, as well as Union Berlin.
Thursday's visitors have struggled away from home this season after winning only one of their five competitive away games this term.
Although, they can draw inspiration from the fact they have won three of their last four matches, including a 3-1 league victory over Zulte Waregem at the weekend.
Union Berlin form (all competitions):
Union SG form (all competitions):
Team News
The hosts are unable to call upon the services of Jordan Siebatcheu, Diogo Leite and Fabio Schneider, who are all sidelined with injury issues.
Following a hard-fought 1-1 draw against Bayern, Fischer could be tempted to name an identical starting XI for Thursday's contest.
Having scored five goals as many Bundesliga matches this season, Sheraldo Becker will provide one of Union Berlin's main goal threats.
As for the visitors, they have doubts about the availability of Gustaf Nilsson and Koki Machida, who are struggling with foot and knee problems respectively.
Dennis Eckert Ayensa has come off the bench to score in the last two games, but he may have to settle for a place amongst the substitutes once again, with Karel Geraerts set to name an unchanged lineup.
If Geraerts does opt against making any changes then Victor Boniface will continue to partner Dante Vanzeir in the forward line.
Union Berlin possible starting lineup:
Ronnow; Trimmel, Knoche, Jaeckel, Doekhi, Ryerson; Schafer, Khedira, Thorsby; Becker, Behrens
Union SG possible starting lineup:
Moris; Kandouss, Van der Heyden, Burgess; Nieuwkoop, Teuma, Lynen, Amani, Adingra; Boniface, Vanzeir