Kruse, 25, tore his anterior cruciate ligament in training with Bundesliga club side Bayer Leverkusen last month.
The former Melbourne Victory forward initially - and optimistically - declared his intention was to try and return to fitness with a view to earning a place in Australia's squad to travel to South America in June.
National team coach Postecoglou talked down that possibility soon afterwards and has now reiterated that position, telling Kruse in no uncertain terms not to put his long-term health at risk with a rushed rehabilitation.
"Look, he's unlikely to feature," Postecoglou said.
"It's probably going to come on a bit too quickly for him. From our perspective, he's working already hard on his recovery, he's still a young man.
"He's definitely got another World Cup in him. The most important thing is he does his recovery really well and we'll see what happens from there."
