The hosts head into the match inside the automatic relegation places, while Union moved back up to second in the table after winning in midweek.
Match preview
Despite being thrashed 5-0 at home to Wolfsburg on Tuesday, Sandro Schwarz has received public backing from Hertha's sporting director Fredi Bobic in recent days. "For me, he is not even remotely up for discussion," Bobic told Sky.
However, we have seen such words shortly followed by sackings time and time again throughout football's recent history, with Schwarz's position surely more vulnerable than Bobic would admit in public after the "worst [performance] I have seen this season" to use Schwarz's own words following their most recent defeat.
Hertha trailed 3-0 to the Wolves at half time at the Olympiastadion, before Ridle Baku and Omar Marmoush added more gloss to the visitors' victory during the latter stages of the match. The defeat leaves Die Alte Dame second from bottom in the table, although they are only two points from safety.
In fairness to Schwarz, who joined the club last summer, Hertha's malaise has lasted several years now and they have routinely flirted with relegation - most notably when beating Hamburger SV in the relegation playoff last May - so it is little surprise to see them in their current perilous position.
Having lost each of their last four matches against their city rivals, a home win on Saturday could be the turning point which Hertha need to kick on and avoid being embroiled in that situation once again, or worse.
After failing to win any of their final three games before the World Cup began in November, Union Berlin have returned to action with a bang by winning both of their matches within the past week.
Urs Fischer's side showed their resilience to come from behind against both Hoffenheim and Werder Bremen and claim crucial victories, with Janik Haberer and Kevin Behrens scoring either side of half time in Bremen on Wednesday evening.
Die Eisernen continue to sail new heights under Fischer's tutelage, with knockout ties against Wolfsburg and Ajax in the DFB-Pokal and Europa League respectively awaiting them next month.
While finishing inside the top four positions of the Bundesliga for the first time in the club's history will be the 56-year-old's priority after missing out by a single point last season, the former Basel boss would clearly love to deliver Union's first ever major trophy in the modern era.
In the meantime, though, he and his players will be hell bent on earning a fifth successive derby win on Saturday, which would pile even more misery on their rivals while moving themselves level on points with league leaders Bayern Munich ahead of their clash against Eintracht Frankfurt later in the day on Saturday.
Hertha Berlin Bundesliga form:
L
L
L
W
L
L
Union Berlin Bundesliga form:
L
W
L
D
L
W
Union Berlin form (all competitions):
W
W
L
D
L
W
Team News
Hertha will be without the suspended Agustin Rogel, who received his fifth caution of the season during Tuesday's defeat to Wolfsburg. Filip Uremovic will likely start in his place after replacing him at half time in that match.
Stevan Jovetic (muscle), Chidera Ejuke (knee), Kelian Nsona (ACL), Jonjoe Kenny (concussion) and new signing Florian Niederlechner (thigh) are all expected to be sidelined, while Ivan Sunjic and Maximilian Mittelstadt could be at risk of being dropped after also being hooked at half time in midweek.
Union, meanwhile, will make the short trip to the Olympiastadion with a fully-fit squad with one exception: midfielder Morten Thorsby, who continues his recovery from an operation.
Fischer's main selection headache will be up front, where Behrens impressed with a goal after being handed a start in place of Jordan Siebatcheu. The latter is likely to win that particular duel despite failing to score in any of his last nine league games.
Christopher Trimmel's experience should see him also return at right-back in place of Josip Juranovic, who enjoyed a solid debut in Bremen following his move from Celtic earlier this month.
Hertha Berlin possible starting lineup:
Christensen; Pekarik, Uremovic, Kempf, Plattenhardt; Tousart, Serdar; Lukebakio, Boetius, Richter; Kanga
Union Berlin possible starting lineup:
Ronnow; Jaeckel, Knoche, Leite; Trimmel, Haraguchi, Khedira, Haberer, Giesselmann; Becker, Siebatcheu
We say: Hertha Berlin 1-3 Union Berlin
Hertha's relative solidity under Schwarz prior to the World Cup appears to have gone out of the window since returning to action last weekend, with disappointing defeats to VfL Bochum and Wolfsburg seeing them drop into the automatic relegation places.
As such, we are struggling to see beyond a fifth consecutive victory for Union in the Berlin derby, with Fischer's side looking well set to challenge for a Champions League qualification position once again this season.