The away side have endured a mixed pre-season schedule so far, and now face a tough visit to the Stadion An der Alten Forsterei to face a strong Bundesliga outfit in Germany's capital.
Match preview
Forest fans continue to dream of their season opener at Newcastle United on August 6, a match that will officially end their 23-year wait for Premier League action.
Reds boss Steve Cooper remains fully focused on their preparations for the 2022-23 season ahead though, which continued with a 3-1 victory over Union's city rivals Hertha Berlin at Burton Albion's Pirelli Stadium on Wednesday evening.
Lyle Taylor, who recently returned from a six-month loan spell at Birmingham City in the Championship, netted a first-half brace against their German opponents in a bright start.
Hertha halved the deficit before the break, but after a quiet second 45 for both sides, a late own goal helped Forest to restore their two-goal advantage and a relatively comfortable victory in the end.
That win followed a goalless draw with League One side Barnsley last Saturday, which had come after a victory over Burton and a defeat to Coventry City, leaving a fairly inconsistent look to Forest's success during the summer so far.
Cooper will be eager to regain the consistency that his side displayed in their charge for promotion at the end of last season, which could be required for his side to avoid a disappointing immediate return to the second tier when their eagerly-awaited campaign gets started in two weeks.
Meanwhile, hosts Union continue their preparations for a fourth successive campaign in the Bundesliga this season, which will follow a hugely impressive return to the top flight across the past three years.
After achieving a mid-table finish in the 2019-20 season, Die Eisernen finished seventh in 2020-21 to qualify for the inaugural Europa Conference League campaign, and although that proved a disappointment in the end, Union went one better by qualifying for this season's Europa League with an impressive fifth-placed finish last season.
Urs Fischer's side even came within a whisker of stealing Champions League football off giants RB Leipzig following a remarkable finish to the season, which left them just a point behind following the conclusion on May 14.
The Berlin outfit continue to surprise many given their lack of star names and budget in the capital, but Fischer has put together a hugely organised outfit that are likely to provide a huge test for Forest on Saturday.
The hosts have won four, drawn one and lost just once during their six pre-season matches to date, and the schedule concludes with the weekend hosting of Premier League Forest, before opening their competitive campaign with a trip to amateur outfit Chemnitzer in the first round of the DFB-Pokal on August 1.
Union Berlin pre-season form:
Nottingham Forest pre-season form:
Team News
After naming a fairly settled squad for much of last season, Fischer is unlikely to deviate too far from his first-choice 11 in Union's final friendly of the summer on Saturday.
Timo Baumgartl continues to remain absent whilst he continues his battle against cancer, which means Paul Jaeckel should continue alongside Robin Knoche and Dominique Heintz in Fischer's back three.
Niko Giesselmann and captain Christopher Trimmel could offer the width in the wing-back areas, whilst summer-recruit Jordan Siebatcheu should line up alongside Sheraldo Becker in attack.
As for the visitors, Taiwo Awoniyi will be handed the opportunity to make a quick return to the Stadion An der Alten Forsterei following his club-record move from Union to Forest earlier in the summer.
Harry Toffolo made his debut for the Reds just hours after signing for the club from Huddersfield Town on Wednesday, and was later joined at the club by Terriers teammate Lewis O'Brien, who was not signed in time to make his debut against Hertha.
The midfielder should feature here, alongside fellow summer arrivals Dean Henderson, Neco Williams, Moussa Niakhate, Giulian Biancone, Omar Richards and Awoniyi.
Union Berlin possible starting lineup:
Ronnow; Jaeckel, Knoche, Heintz; Trimmel, Pantovic, Khedira, Haraguchi, Giesselmann; Becker, Siebatcheu
Nottingham Forest possible starting lineup:
Henderson; Worrall, Niakhate, McKenna; Williams, Cafu, O'Brien, Richards; Johnson; Taylor, Awoniyi
We say: Union Berlin 2-1 Nottingham Forest
Although Forest have enjoyed an excellent transfer window so far, it may take some time for several new members of the squad to gel with their teammates.
For this reason, as well as the quality on display and fitness advantage from Union, we can see the hosts coming out with a narrow victory here to conclude their positive summer on a high.