Salah returned to partial training on Wednesday after sustaining the strain in the 1-1 draw with Iran last Friday, as the Egyptians picked up the point they needed to progress to the knockout rounds for the first time.
"Salah is a passionate player and he is very much looking forward to making his own contribution," Hassan said.
"I'm not going to run any risk unless I'm 100% sure he is fit and raring to go tomorrow.
"We look forward to him playing tomorrow, but we're not sure if he's going to be in the starting lineup."
Salah has scored once at the tournament so far, netting his side's second goal as the Egyptians battled back to hand New Zealand a 3-1 defeat in the group phase.
He asked to be substituted with 33 minutes remaining against the Iranians, and his battle to be fit has overshadowed his team's preparations for one of the biggest games in their history.
"He is one of the best players globally, and I'm very lucky to work with him, and I'm very happy with our work together so far," said Hassan.
"I have managed to deploy him tactically and technically speaking, and he has surpassed the capabilities that people had expected of him so far."
Tony Popovic's Australia side are expected to present the Egyptians with a physical challenge but Hassan is confident his team will be well prepared to deal with that test.
"On the African continent, we have vast experience with tall players, comparable to the Australia side we're going to face tomorrow," he said.
"It's the same as New Zealand, Belgium and Iran. We have dealt so far with such conditions...
"Every team has its weaknesses and strengths and we're well prepared to deal with whatever we're going to face.
"(Diego) Maradona wasn't the tallest of players, (Lionel) Messi isn't either. It's not about tall or short. We're not playing rugby here, we're playing football. Not American football, but football and we're fit and raring to go."
