Kevin Walters wants Australia to shore up its right-edge defence against Cook Islands after conceding several tries there in last week's 36-22 win over Fiji.
For Saturday night's match, Cameron Munster will play five-eighth and Tom Dearden halfback, marking Australia's third halves pairing in as many games.
Mitchell Moses partnered Munster in the 24-22 opening win over New Zealand, but an injury ruled him out of the tournament. Dearden then came off the bench, before starting alongside Sam Walker against Fiji.
Walker has been left out of the 19-player squad, though Walters said the selection did not settle his semi-final plans.
"It doesn't mean anything towards next week. It is about this game here," Walters said after Friday's captain's run in Townsville.
He added, "There's not much between the two. It's just a decision that I have to make as the head coach and I'm comfortable with the decision that I've made."
Walters said Walker had handled the omission well and rejected any link to the Sydney Roosters withdrawing their offer to extend the playmaker's contract beyond 2027.
"No, nothing to do with that," he said. "Sam's a very mature young fella. Just having a chat to him the last few days about what's happened, he's on top of it. So that's got nothing to do with anything that we're doing here."
Walker remains in contention for the semi-final on November 8 at Allianz Stadium.
Walters wants Australia's spine to improve its communication and get the ball to the team's strike players at better moments.