Roar coach Mike Mulvey revealed that Smith, who has been forced to sit out training again on Friday, has been struggling with the complaint for the past five weeks.
"Every game he has been in doubt, to tell you the truth, but he has battled through brilliantly," Mulvey said.
"He is the leader of the group and I can't speak highly enough of his commitment to the cause.
"We need to protect Matt but also make sure we have the right team on the park so we will make a decision as late as possible."
New signing Jade North is yet to prove his fitness after linking up with the club this week, with Mulvey all but ruling him out for the Suncorp Stadium meeting.
"We signed Jade with a view to the long-term future not the short term ... he is not quite ready yet," Mulvey said on Friday.
"I don't want to put him out there and he is lost for five to six weeks - that would be ludicrous on my behalf."
Already hit by key midfielder Erik Paartalu's mid-week move to China and Central Coast Mariners-bound winger Nick Fitzgerald's banishment to the youth team, Mulvey's options are limited.
With Roar languishing in eighth spot, Smith warned that if the back-to-back A-League champion keeps going the way it is it won't have to worry about finals football.
Roar is playing a dangerous game with its inconsistent results.
Two weeks ago, after Brisbane had recorded back-to-back wins for the first time this season, Smith told The World Game the team couldn't even begin to think it was back as a major force until it went on a run of six or seven games without defeat.
Since then, Brisbane has lost two in a row - 3-2 against Melbourne Heart and 1-0 to Newcastle Jets, with both games on the road.
"At some stage, the mathematics when it comes to positions on the the competition table is going to become an issue for us if we keep it up like this," Smith said.
"It's about getting some momentum going now. We've been far from our best the last couple of week but we know we're capable of getting back to our best.
"We know that on our day we're capable of doing very well but it just isn't happening week in and week out.
"The motivation and the hunger are still there among the guys but consistency is something we've been struggling with all season.
"I'm not saying it's playing on our minds but we know we have to get that consistency back to a high level if we're going to make a push in this competition."
Smith conceded it was possible Roar could be suffering from a championship hangover.
"I know we're doing the work because I see it every day at training," he said.
"Maybe in games we just expect things to happen at times. We might believe things are going to happen and that everything will be OK. But we have to make it happen.
"Too many times, we've been undone by soft goals, and that's the effect of a lack of concentration. We have to be smarter if we want to stop that happening."
Wanderers has been a nuisance for Roar this season, having won both games and Smith knows it's going to be another difficult assignment.
"The Wanderers have had a fantastic season so far," he said.
"They have surprised a lot of people with how well they've played. They're very well organised, they have specific game plans for specific opponents and their coach isn't afraid of using his full squad.
"Winning is a habit that is hard to break and that's the habit they're in.
"We still believe in ourselves and we'll be trying to reverse the trend on Sunday.
"We can't believe we're back until we get there but we know we can get there. This is a very important game for us."