Son scored a hat-trick as Tottenham won 5-2 at Burnley on Saturday, and he was operating centrally after Richarlison was dropped.
Spurs also signed versatile forward Brennan Johnson from Nottingham Forest on deadline day, but brought in no traditional No9 in the mould of Kane after his exit for Bayern Munich.
Asked whether Son’s ability to play centrally was the reason, Postecoglou said: “It’s not exactly why, but it’s one of the reasons. I’ve got a picture in my head of what I want the team to look like and I keep saying that we’re still at the beginning.
“It’s about putting all the pieces together and, at the same time, not neglecting what’s right in front of you. Sonny, whether he’s playing central or wide, has got all the characteristics. He can play in any system, but the way we play, he’s ideal.”
All of Spurs’s five goals were scored by Postecoglou’s new-look leadership team, with Son’s hat-trick complemented by goals for vice-captains Cristian Romero and James Maddison.
The Spurs boss said: “I thought today was a real testament to Sonny, Madders and Romero. They all scored, but those three I’ve thrust into leadership positions and the way they’ve embraced that responsibility with not only words but actions, not just on game day but on a daily basis — that’s as encouraging for me as anything. As fantastic players as they are individually, they’ve all really bought into that team ethic.”
Quizzed on whether the transfer window went as he had hoped, the Australian replied: “When you go through these things, you always understand that there are so many moving parts. You rarely come out of it with an ideal picture, but that doesn’t mean it isn’t a picture that can still work.
“We’ve still done a fair bit in a short space of time. We’ve virtually changed half the starting line-up, the way we play, the way we train, totally new coaching staff and training. It was never going to be one window, this rebuild. Where we sit at the moment, I’m really happy with the players we’ve brought in.”