The pair were ruled out of the Wanderers' 2-1 loss to Newcastle on Saturday after being injured during the AFC Champions League clash against FC Seoul in Korea Republic on Wednesday.
The Socceroos are due to depart for Europe on Sunday for the matches against world champion Germany in Kaiserslautern on Thursday morning (AEDT) and FYR Macedonia in Skopje.
Football Federation Australia (FFA) on Sunday confirmed Spiranovic will not be joining the squad and will be replaced by fellow World Cup defender Bailey Wright.
Juric was a late exclusion from the starting lineup for the Wanderers' midweek ACL game after straining a groin complaint and appears highly likely to miss out on national team duty.
Popovic revealed Spiranovic's hamstring injury was not as bad as first feared, but he's still likely to be sidelined for at least three weeks.
Juric meanwhile, looks set to be out for a week.
"Spira is definitely out and Tomi I'd be surprised if he goes with the Socceroos. He's a big doubt," Popovic confirmed.
The coach said he didn't feel Juric would be fit to travel but Socceroos medical staff will make the final call.
"For me he's ruled out today injured," he said.
"If he stayed here in Sydney, it would be highly unlikely he could be involved next weekend.
"But that's not my decision. If the Socceroos want to take him, they take him.
"But for me, if he didn't play today, he's not fit."
