The former Leicester City man has been unavailable since sustaining the severe issue in November's 4-1 loss to Chelsea, sitting out Spurs' last 11 matches across all competitions.
In that time, Tottenham have only managed four wins from 10 Premier League fixtures to lose their grip on first place in the table, having posted 26 points from 30 on offer while Maddison was fit.
However, the Lilywhites teased the 27-year-old's return on social media on Wednesday, confirming that their summer signing was back in training and sharing an image of him on the Hotspur Way pitches.
Postecoglou was unsurprisingly asked about Maddison's fitness as soon as Thursday's press conference got underway, and the Tottenham boss confirmed the good news that the England international is raring to go for the visit of City.
"Madders has been training with us, has had a full training week. He's in a good place," Postecoglou said, while also announcing that Maddison would be ready for selection from the first whistle.
The 27-year-old seamlessly slotted into Postecoglou's attacking system upon his summer arrival from Leicester, scoring three goals and setting up six goals in his first 11 Premier League games for the club and winning August's Player of the Month award.
Maddison's comeback is one of four fitness boosts Tottenham have received ahead of Friday's tantalising tie, as Dejan Kulusevski has recovered from the illness which kept him out of the 2-2 draw with Manchester United on January 14.
Postecoglou also revealed that Dane Scarlett (knock) and Ben Davies (thigh) have also returned to team training, but Giovani Lo Celso (thigh), Manor Solomon (knee) and Alejo Veliz (knee) remain sidelined, despite reports that Solomon would be pushing for a return on Friday.
Speaking to Tottenham's media channels before his press conference, Postecoglou added: "Everyone has got through well from the last game, we gave the boys a few days off which I think was good for them.
"Ben and Dane Scarlett have also begun training with the group, we're getting the numbers back. Gio's still a little bit further away, not too far away, just depends on his recovery. Our next cabs off the rank are Gio, Manor and Alejo."
After making his first appearance of the season against Burnley in the third round, Ryan Sessegnon - who underwent thigh surgery in the summer - missed the draw with Man United with what Postecoglou described at the time as a "slight niggle".
The Australian has now admitted to reporters that Sessegnon's issue was a "reaction" relating to his recent comeback, although he should be back in action for the visit of Brentford on January 31.
"Ryan's still in rehab. We're hoping Sess will rejoin us next week if all goes well. Pretty much a reaction to so long out. We have to be careful with him. It's something he's been carrying for a while," Postecoglou added.
In addition, Tottenham remain without Pape Sarr (Senegal), Yves Bissouma (Mali) and Son Heung-min, who scored an injury-time penalty for South Korea to rescue a 3-3 draw in their final Asian Cup group match with Malaysia on Thursday.