The Australians fielded a largely Olympic under-23 team and paid the price with a 1-0 loss to China on Sunday - their first home World Cup qualifying defeat in nearly three decades.
Goalscoring midfielder Cahill has missed Australia's qualifiers after foot surgery and is aiming to be back for Everton in August, while Newcastle United striker Mark Viduka has an Achilles injury.
"Timmy Cahill, I have my doubts, because of his injury, and that's the same with Mark Viduka," Verbeek told reporters on Monday.
"They are available the moment they are fit and ready and that's the big question we have to wait for."
"But again we have eight games to go, the final game is in (next) June. They will come back."