Australia coach Guus Hiddink praised Kewell's contribution but said the Socceroos still had to be careful with the Liverpool winger.
"I have to be careful with Kewell as he will not be totally fit but we need him and we need someone who can open up the defence of other teams," said Hiddink.
"He has worked hard. Of course he's not game fit, but I'm happy to see him now. He must, in the upcoming days, keep up the same level of work, so he can get more game fit. But the development is okay.
"If he doesn't have any reaction from the injury it might be possible that he plays in our final warm-up against Liechtenstein [on Wednesday].
"He must join in for some part of the game, it would be very beneficial for himself to play if he can."