The Spurs head coach has said Maddison is "ready to start" the FA Cup fourth-round tie at home to the champions on Friday, having trained all week. The England playmaker has been sidelined since suffering ankle ligament damage in the defeat to Chelsea on November 6.
City's Kevin De Bruyne made an instant impact on his return from injury in the 3-2 win over Newcastle on January 13, coming off the bench to create one goal and score another, and Postecoglou was asked if Maddison could make a similar impact tomorrow.
"I don’t want to put those expectations [on him], but I know what Madders expects," Postecoglou said.
"And in training, you wouldn’t know that he’s missed so much. The quality is there straight away and everyone notices it. And he’s looking good physically.
"He’s the kind of guy who will want to make up for lost time and come back in and make an impact straight away."
The layoff was the longest of Maddison's career and Postecoglou revealed it had been hard on the midfielder, who was sent to Dubai for a change of scene before Christmas, accompanied by a member of the club's medical staff.
"He's not been low but it was tough for him," Postecoglou said.
"Because he does love his football, he loves the environment of football clubs, he loves the dressing room. He’s kind of a force within that.
"It’s hard for all players when they’ve got to go through rehab, especially a character like him. I suggest that our sports science staff wouldn’t enjoy the one-on-one with Madders. He’s more of a guy who wants to be in the group.
"We did send him away in the middle of it. We felt it was good for him to get away with his family, we sent a physio with him. I think that helped bridge that time. When he got back from that, he was refreshed. Once he could see the finish line of, ‘Ok, I’m getting to the tail end of it’ … you could see his spirits lift. It’s been good to get him back."
"[Going to Dubai] was to just to replicate to get away from this environment and do exactly what he would do here in another environment," Postecoglou added.
"He went away with his family. We did that [Cristian] Romero [who returned to Argentina] and Gio [Lo Celso] is doing the same thing.
"For players to come in on a daily basis and watch the guys train and not be part of it, it is not easy. If we can somehow accelerate that process by changing something. .. some don’t and the like to do it here. But with Madders we felt that way."
Spurs have not won the FA Cup nor reached the final since 1991, while their trophy drought in all competitions stands at 16 years.
Though Postecoglou has said Spurs are in the title race, the FA Cup is by far their best chance of silverware this season, provided they can continue their fine record against City at the Tottenham Hotspur Stadium and knock out the holders.
"The fans have had to sit through year after year of not winning a trophy"
Postecoglou says he wants to win silverware for the supporters but reiterated that his aim at Spurs is to consistently challenge for honours, rather than sate fans with a single trophy.
"It’s very important [to win something], not because of any other reason but what it would mean to our supporters," he said.
"We, as in managers and players, come and go. Even the great ones at some point finish.
"But the supporters are always there. They’ve had to sit through year after year of not winning a trophy. Watching other clubs win trophies so you know what it means.
"But I’ve said before that can’t charter my course of what I want to build here. I want to build a team that brings success and challenges for trophies every year.
"Because while one trophy will satisfy that thirst, which I understand, if the following year we struggle and fall back to mediocrity then it will quickly get forgotten. And that’s not what this club is about.
"My goal when I was brought in was to take this club to being a club which competes for honours every year, and that’s what I’m focused on.
"This game is part of that process obviously. But I’m under no illusions of what bringing a trophy to this club means to the supporters, I understand that, but my objective within that is to give them that joy on a regular basis and not just as a one-off."