Bentancur has been given a seven-match domestic suspension by the Football Association for the use of racist language during a media interview earlier this year and while Spurs have appealed against the length of ban, the Uruguay international will definitely sit out the Etihad Stadium clash on Saturday.
It has added to an already difficult fortnight for the club with vice-captain Cristian Romero forced to return early from national team duty due to his ongoing toe issue which will rule him out of the fixture against Pep Guardiola's side, while Wilson Odobert also had hamstring surgery last week.
Micky van de Ven (hamstring), Mikey Moore (virus) and Richarlison (hamstring) are other players unavailable and even though Premier League champions City have lost their last four games, they have a plethora of key personnel back and will want to toast Guardiola's new contract with a victory.
"It's really important when they come back here again we move on pretty quickly," Postecoglou reflected, referring to the 2-1 home loss to Ipswich before the international break.
"They understand we still have to do our review and we did that. We looked back at the areas we need to be better, but I don't get the sense the lads are down in the dumps in any way.
"I think there is a determination there to get back to the level we need to be and get consistency around that.
"You are playing City at their place and they have a pretty imposing record there. Those four losses have all been away from home.
"Ee know it is never an easy task at City. It's great that Pep has re-signed. It's fantastic for the Premier League. He keeps setting the standard, which is great for all of us trying to mow him down."
Defeat for Spurs would make it three losses in a row, but much of the focus over the past week has been on Bentancur's suspension.
Bentancur was charged by the FA on September 12 with an alleged misconduct breach in relation to a media interview, which emerged in June and showed the Spurs midfielder being asked by the host of Canal 10 show to show the shirt of a Tottenham player.
Asked by the host to show the shirt of "the Korean", Bentancur replied: "Sonny's? It could be Sonny's cousin too as they all look the same."
Bentancur's ban is only one game above the standard minimum that can be applied for misconduct where discriminatory behaviour or language in a TV interview is an aggravating factor.
Postecoglou explained: "We'll accept whatever penalty comes our way. We believe that the first one was a little bit harsh so we've appealed that, which I think is our right."
