The Preston North End friendly showcased the paucity of resources Postecoglou has to work with. The line-up was (perhaps) as near as injuries permit, to that to face Midtjylland.
The Ghost of Disasters Past
In thinking about context for this piece I looked back on the starting XI’s for each of the disasters to befall Celtic in the last 7 seasons I’ve been capturing data. And there has been at least one EVERY season.
If you are easily depressed, look away now.

Not all of these were fatal defeats in terms of progress, but all were awful performances against much less well-resourced sides.
Any of these line ups you think is weaker than what will take the field vs Midtjylland? The 14/15 team at a push (had Forster, van Dijk, Lustig and a young McGregor!)?
In most cases, 1 or 2 disruptions mainly to centre back and striker (note M. Dembele doesn’t feature in these matches) was enough to cause systemic poor performance.
This time around, apart from central midfield, we could argue EVERY position has uncertainty and compromise ahead.
So, deep breath, that’s where we are.
Pre-Season
What did we learn from pre-season? 33 players over 4 matches. Many of the younger players given an opportunity. The usual pre season injury headaches. Doubts over players looking to leave.
None of the matches would normally warrant much scrutiny but the threadbare depth of experience and proven talent in the squad, a new manager and the imminence of Champions League qualifiers has all added to the attention.
In terms of highlights, the first half vs Charlton Athletic provided 45 minutes of a style of football recognisably Postecoglou-esque. A 2-0 lead was not as important as the manner which players like Ralston, Taylor, Montgomery, Ajeti seemed to adapt to new demands. Shaw added a rangy box to box aggression hitherto missing. And it looked very good.
Low light was the performance from a similar starting XI against Preston North End. This is a mid-table Championship side with proxies for Midtjylland style in terms of organisation, their height and set piece prowess. Celtic barely won first contact at any high ball into the box and in particular Urhohgide (6’ 2” and excellent vs Bristol City) was bullied all over by Ched Evans (6’ 0” and journeyman) and subbed at half time.
Of the starting XI, I felt only McGregor, Turnbull and (don’t shoot me) Barkas are of the calibre Celtic need to navigate a Champions League qualification. As we have seen above, far more starred sides have failed badly at this point in the season.
Moving On Then
Midtjylland are in a state of transition with a new manager also. Some of their better players from last season are in the same holding pen that Ajer, Ntcham, Shved and possibly Christie and Edouard are in (although the latter two have made the official UEFA squad). Their main striker, Kaba, has downed tools.
In summary they are an attacking, high pressing side. They are very big and physical and will be direct up to the striker (4-2-3-1) with goal threats from all the front four. There will be a heavy reliance on set plays and crosses into the box and oh-my-god this all sounds horribly familiar, doesn’t it?
No other recent centre half comes close to Welsh losing 1.8 aerial duels per 90m, and he will likely be flanked by Ralston and Taylor with Soro providing the protection. Oh, and he looked most uncomfortable on the left side of defence which also served to limit his passing effectiveness. This is a very small Celtic side, so that is the first challenge.
Let’s start with the (semi-)knowns:
Barkas has been first choice in friendlies and no reason to think he won’t start.
If Soro is fit then the midfield three of Soro, McGregor and Turnbull are definite albeit that is a very “light” midfield.
Ajeti has started every friendly and scored 2
Injuries: we’ll be without Jullien, Bitton Forrest, Johnston, Dembele at a minimum
Shved, Ajer and Ntcham are not the squad
None of Bolingoli, Rogic, Christie, Edouard or Griffiths will start due to next to no minutes
After that, does Postecoglou:
Use the preseason appearances as a guide and ignore the Preston debacle
Pull a plan B out the hat
Option A could lead to a line-up of (4-2-3-1):

Honestly? We might have to prepare for Artmedia Bratislava #2 or worse.
Option B – what could that look like?
In terms of matching up to the opposition and at least being physically competitive, can I suggest (4-2-3-1):

You can mix and match yourself and shoot me down but really, there are no good options here. This is looking like the weakest Celtic line up since…. I do not even know. Bunting will be out if Bitton makes it. Which is not a line I ever thought I’d type.
Conclusion
A “what will be a formation in our next match” does not usually warrant an article and if it did, would be about 150 words.
Nearly 900 words in, and the scale of the work Postecoglou has on is blindingly apparent if it wasn’t already.
As I have shown, previous disasters occurred with much better and more experienced teams than is likely to be available tomorrow. It’s either “do your best kids”, or some form of Championship Manager tinkering.
And that’s all I have on that.
Patience.