It seems ridiculously early to be making a call on his position, and yet there is also an ominous inevitability about the direction of travel. This afternoon's meeting with Chelsea has been described as 'pivotal', with one report down south suggesting it could be over for Postecoglou if that winless stretch extends to eight. It is, even by modern football standards, an absurd situation.
But what's most baffling is how Forest have found themselves in such a self-inflicted mess.
They were among the Premier League's biggest success stories last season, with fans united behind manager Nuno Espirito Santo as he led them back to Europe for the first time in 30 years. They were even promoted from the Conference League to the Europa League after Crystal Palace were denied entry to the latter, their presence deemed contradictory to UEFA's rules on multi-club ownership.
Espirito Santo had his side as high as third in the table with as little as five games to play, before a costly late dip dropped them to seventh. It was, however, still a significant overachievement for a team that finished 17th only a year earlier.
Their Portuguese manager had crafted a team with identity, with heart and talent in equal measure, and it intoxicated a fanbase that had for so long been starved of success. Some regression to the mean was, perhaps, inevitable this season, but they have descended into shambles at a baffling rate.
The first visible crack appeared when owner Evangelos Marinakis entered the pitch to have an animated discussion with Espirito Santo following a 2-2 draw with Leicester City in May, one that significantly damaged their long flirtation with Champions League qualification.
Both men tried to downplay the incident, citing 'confusion' around what Marinakis described as a 'misjudgement' from club medical staff over an injury to forward Taiwo Awoniyi. After colliding with the goalpost as Forest pushed for a late winner, the striker signalled to Espirito Santo that he wanted to stay on, seemingly clearing the manager to bring on Jota Silva for Elliot Anderson as his final substitute.
Moments later, however, Awoniyi went down again and was unable to continue, prompting Marinakis to make a beeline for Espirito Santo at full-time. Ex-Manchester United defender Gary Neville branded the incident 'scandalous' on Sky Sports, and Forest moved to quell the growing PR storm by banning the country's most prominent pundit from their stadium.
In August, Espirito Santo publicly declared his relationship with Marinakis was now 'not so good'. The appointment of former Arsenal sporting director Edu as 'head of football' had proved a turning point.
Reports claimed he and Espirito Santo did not see eye-to-eye, and that in turn fuelled friction between the manager and Marinakis. By September 8 Espirito Santo was gone, just three matches into the new Premier League season.
His replacement had already been lined up, with Postecoglou's arrival confirmed the following day. A proven winner in multiple countries, Forest bet on him as the man to reunite the club in the way he most notably had at Celtic.
But the primary risk was obvious.
Espirito Santo's success was built on foundations of defensive discipline and a counter-attacking ethos. Hiring Postecoglou, then, was to put a squad built for a specific purpose in the hands of a coach who demands something completely different.
The Greek-Australian's commitment to high-pressing, high-risk football was the enduring talking point from his spell at Tottenham. When Spurs were good - that's Angeball. When Spurs were bad - that's also Angeball.
Postecoglou, painted as a stubborn idealist, embraced pragmatism when he took a rather more workmanlike route to winning the Europa League - before Tottenham sacked him anyway - but his preference will always be for front-foot, attacking football.
'It's who were are, mate', he declared after nine-man Tottenham's defensive line refused to drop past halfway in a 4-1 loss to Chelsea in November 2023.
Postecoglou is possibly the most 'you know exactly what you're getting' coach in the Premier League. The 'what', in Forest's case, is the stylistic opposite of the man who came before him, and takes time to implement.
When it clicks, it is spectacular. Postecoglou is a charismatic figurehead, wants to entertain, and inspires loyalty in players. Supporters worshipped him at Celtic.
If you go all-in on 'big Ange' knowing that the conditions aren't primed for his style of play, then you have to show patience. But with Marinakis apparently on the verge of making another change in the dugout, it points to a seriously muddled strategy from which Postecoglou could become collateral damage.
All this would surely have been discussed before contracts were signed and announcements made, but Forest seem to have underestimated just how unpopular the decision to sack Espirito Santo would be.
So not only was Postecoglou handed a significant challenge in recalibrating his predecessor's team during a busy fixture schedule, it then became clear that a poor start would put him on the back foot with a fanbase who never wanted change in the first place.
Postecoglou's first six games came within 23 days of his arrival, which leaves precious little time for work on the training pitch. A significant chunk of his squad have then gone on international duty, during which last season's top scorer Chris Wood pulled up injured for New Zealand.
The taunts aimed at Postecoglou from Forest fans may have felt personal, but they probably stem more from a place of still being in love with the other guy. From the outset, the man who so effortlessly charmed the green half of Glasgow acknowledged he would have to work to win over the Forest faithful, but prospects of a prosperous union have only faded further in the last month.
As absurd as it is, defeat to Chelsea this afternoon could render him another victim of football's cruellest equation. The value of 'X' doesn't really matter in this scenario, because once you're in it, there's very rarely a way out.