Cahill has been struggling with a foot injury since hurting it against Middlesbrough on the weekend but it seems it is not related to the injury he has had so much trouble with in the past.
"My metatarsal (which he broke this year) is brilliant now but I've got other little niggles that you pick up from coming back from such a long spell out," said Cahill.
"But it's just one of those things that I've learned to deal with and maintain it well over the last month or so.
“Obviously he's not going to be very happy with me playing when I've got a few niggles and things," Cahill said.
"The club does come first, they pay my wages, but this is a World Cup qualifier and I think it's one of the most important games of our group.
"I feel that it's really important that everyone as a collective group puts as much into this campaign as we can because of what it means to our country."