The attacking midfielder, on loan from Scottish Premiership club Celtic, limped off early in the second half of Victory's thrilling 4-3 win at home to Adelaide United.
Rogic, likely to feature prominently for the Socceroos in Brazil, sustained the knock in an accidental collision with team-mate Leigh Broxham, and appeared to be in some distress as he was helped from the field.
Although the full extent of the problem is yet to be determined, Muscat is hopeful the 21-year-old can still travel with the Victory squad to China for their AFC Champions League group stage opener against Guangzhou Evergrande on Wednesday night.
"I don't know the full extent at this time," Muscat said.
"He did go over his ankle. I'm optimistic like always that he'll be OK and it's not too bad. But I said that Adrian Leijer," he added, referring to the centre-back, who sidelined with a series of facial fractures.
When pressed on Rogic's likely availability for the flight to China on Monday, Muscat said: "Again, I'm optimistic. The game's four days away.
"Look, it didn't look too great when he was coming off. He couldn't bear much weight. But we've got a very confident medical staff and if there's any chance of him being available he will, because they'll get him right.
"We won't take any silly risks but if there's a possibility that he could be fit, he'll be travelling."
As for the game itself, Muscat was determined to focus on the positives of his team's fluid attacking performance, despite watching Victory's leaky defence continue to ship goals at the back.
"(I) probably haven't seen a better game of football here in a long, long time," he said.
"It must have been a great game to watch as a neutral. I would have liked it a little bit easier in the last ten minutes, but that's the way it goes."
