Ex-Ireland captain Keith Wood believes there are still "positions up for grabs" in the Irish starting team.
Joe Schmidt revealed the XV that will start in the final pool game against Samoa.
That saw multiple changes from the win over Russia. But it is unclear how Schmidt aims to line-up for a likely quarter-final against either New Zealand or South Africa.
For Keith Wood, nothing is nailed down definitively and he told OTB AM about the areas under scrutiny in his view.
"I still think there are positions up for grabs," he said.
"I think Rory Best has to play well. He has to win his line-outs and he has to do as well as he possibly can. Our back-row also need to play well. We need to get over the gain-line.
"Because at the present moment in time, the ball has been very slow for us. I think Conor Murray has been a little bit slower to the ball because he's fighting for it an awful lot.
"He's not running onto it. It's not presented on a plate to him like it is to some of the other teams.
"I think it's a really big day for Tadhg Beirne because Peter O'Mahony has always been picked.
"The one thing I do like about having Peter O'Mahony on the bench is I feel we're very light in the last 20 minutes in terms of leadership.
"And I'd like to have a leader on the field in the last '20. We've been taking off our leaders and I don't like that at all."
He also shared his thoughts on the chaos caused by Typhoon Hagibis with some pool games cancelled.
"You wonder is there not a contingency to be able to play a game within closed doors?" he said.
"Just where you can get a proper result and give some sort of idea of equity. Because it takes an element of the sporting side out of it actually.
"Because suddenly someone is rested more and somebody gets through with a match they should have won. Then everything's in the lap of the Gods.
"For me, it's not that [World Rugby]'s decision-making isn't right now. It's whether their decision-making and some of the risk assessment early on wasn't thought through."
You can watch the full OTB AM chat with Keith Wood at the top via YouTube.