Without a victory in seven matches, the hosts find themselves three points clear of the bottom three, while the visitors remain six points behind Bayern Munich with four games to play.
Match preview
Augsburg looked set to forget about relegation when they notched four victories in seven matches between January and March, claiming 1-0 wins over Borussia Monchengladbach, Bayer Leverkusen and Hoffenheim before defeating Werder Bremen.
However, Enrico Maassen's side have failed to find another win since then, taking four points from a possible 21 to reignite relegation fears in Bavaria, with Augsburg hovering just three points above the dreaded relegation playoff spot.
Although Augsburg have lost only two of their last six games - drawing with Schalke 04, Wolfsburg, Stuttgart and Eintracht Frankfurt in the process - Maassen's men will be desperate to return to winning ways before things get any worse.
On a brighter note, Augsburg have enjoyed a good deal of success at the WWK Arena in 2023, losing just one of their seven home league games since returning from the winter break, with four wins coming in that time.
It is also worth remembering that Augsburg went to the capital back in November and held Union Berlin to a 2-2 draw, coming from behind on two occasions to snatch a point, so they will fancy their chances of frustrating high-flying Union once again.
Having played out a goalless draw with Bayer Leverkusen last weekend, Union Berlin must return to winning ways if they are to keep pace with Bayern Munich and Borussia Dortmund, who have opened up a gap at the summit.
The Iron Ones trail second-placed Dortmund by five points, while table-topping Bayern find themselves six points clear of Union, so Urs Fischer's men will need to claim all three points at the WWK Arena to keep their title dreams alive.
That said, whatever happens between now and the end of the season, Union Berlin can be proud of what they have achieved in 2022-23, as only Bayern Munich have suffered fewer defeats than Fischer's side this term.
On top of that, Union boast the best defensive record in the division, having conceded 31 goals in 30 games, with first-choice goalkeeper Frederik Ronnow conceding just 20 goals in 25 appearances while keeping 10 clean sheets.
In addition to losing only one of their last eight Bundesliga encounters, the Iron Ones have won four of their previous seven away league games, setting themselves up for a strong - and potentially triumphant - end to the campaign.
Augsburg Bundesliga form:
D
D
L
L
D
D
Union Berlin Bundesliga form:
W
W
L
D
W
D
Union Berlin form (all competitions):
W
L
L
D
W
D
Team News
Injury-hit Augsburg could be without as many as eight first-team players this weekend after veteran midfielder Julian Baumgartlinger joined the club's causality list during last weekend's draw at Frankfurt.
Andre Hahn and Tobias Strobl remain long-term absentees, while Iago, Mergim Berisha, Fredrik Jensen, Rafal Gikiewicz and Reece Oxford are also expected to miss Saturday's clash.
Having chalked up eight goals and six assists this term, Ermedin Demirovic will continue in attack, with Renato Veiga and Mads Pedersen occupying the full-back roles in a 4-4-2 formation.
By contrast, Union Berlin boast an injury-free squad ahead of Saturday's showdown, although centre-back Diogo Leite is suspended due to an accumulation of yellow cards.
Paul Jaeckel is expected to replace Leite in Union's backline, with Josip Juranovic and Jerome Roussillon operating as the wing-backs.
At the opposite end of the pitch, Theoson Siebatcheu will be joined in attack by Sheraldo Becker, who has racked up 10 goals and eight assists across all competitions this season.
Augsburg possible starting lineup:
Koubek; Veiga, Uduokhai, Gouweleeuw, Pedersen; Vargas, Rexhbecaj, Engels, Maier; Demirovic, Beljo
Union Berlin possible starting lineup:
Ronnow; Doekhi, Knoche, Jaeckel; Juranovic, Laidouni, Khedira, Haberer, Roussillon; Siebatcheu, Becker
We say: Augsburg 0-1 Union Berlin
With Bayern Munich and Borussia Dortmund still in sight, we expect Union Berlin to notch a narrow victory over struggling Augsburg, who look set to slide deeper into relegation danger.