As Australia prepare for their do-or-die clash with Thailand in Melbourne, in hopefully their last qualifier for the 2018 FIFA World Cup on Tuesday night, the national coach is still causing consternation by picking players with little or no game time under their belt.
The latest examples were the choice of Brad Smith and Trent Sainsbury for last week's qualifier against Japan in Saitama.
Bournemouth's Smith has played little football this season but got the nod ahead of Rosenborg's Alex Gersbach, who plays more regularly.
It is not the first time Postecoglou has picked Smith when the fullback was not getting enough game time with his club. He also has done it with goalkeeper Mat Ryan and striker Robbie Kruse.
Postecoglou obviously rates the four of them very highly, which is fair enough.
Yet Postecoglou's penchant for going against his principle must cause a degree of disquiet within the group of 30 or so players who are on the Socceroos radar.
Some Australian footballers have traversed the globe in order to find a regular gig and even ended up in leagues or countries they probably would prefer not to be in.
And it must be disheartening for them to learn that despite their efforts and sometimes taking a cut in wages they can be overlooked and the spot they seek is taken by someone with little or no game time behind him.
Disgruntled players would be perfectly entitled to suspect that there are rules for some and different ones for others, as one who has played several times for Australia confided in me.
They might feel inclined to ask what's the point of Postecoglou establishing a policy when he knows he will not stick with it.
Such minor grievances can escalate into dressing-room unrest.
Postecoglou is no mug and certainly does not lack belief in his methods and his players' ability.
So he should have no hesitation in being more forthcoming about his selection surprises and less vague about his justification of them.
If he believes that some players are more worthy of a national jersey than others regardless of how much or how little they are playing then he should say so. People would only complain about that if his judgment goes astray.
He should explain any selection by declaring that he thinks it gives the team the best chance of winning a game. And let's face it, he gets it right more often than not.
Reasonable players would have no problem with that and nor would the media which has had several opportunities to question Postecoglou's unfathomable selections in recent months.
The way things are, his selection policy smacks of inconsistency and maybe reveals a level of insecurity.
His choice of Jiangsu Suning's Sainsbury for last week's match against Japan turned out to be an inspired one even though the Socceroos lost 2-0.
Sainsbury underlined his big-game temperament by turning in a top performance even though he had not kicked a ball in anger since the FIFA Confederations Cup in June.
However his Smith option failed dismally. The Bournemouth man was deployed as a left-sided midfielder and he 'capped' a poor performance by losing his man Takuma Asano who was given all the freedom of the world to slot home his side's first goal in the first half.
Smith, contrary to Sainsbury, appears to struggle at international level.
The point I make is that it is Postecoglou's responsibility to establish a policy regarding his selections and he has every right to tweak it to suit his and the team's needs, particularly since he does not have the luxury of too many stars to work with.
But he should be upfront about this and say that his chosen players are the best men for the job, regardless.
This way there can be no mutterings of discontent.
The buck stops with the coach, of course, and if things go wrong then he would have to lot to answer for.
The players deserve and need a bit more clarity from their coach.