Ireland scrum coach Greg Feek is looking for leaders to emerge from his new-look pack when they tackle Argentina in Sunday's World Cup quarter-final in Cardiff.
The Irish will be forced to reshuffle their forwards due to injuries to Paul O'Connell and Peter O'Mahony and a one-match ban for Sean O'Brien.
Versatile Ulsterman Iain Henderson is set to line up at lock or in the back row, while Donnacha Ryan and Chris Henry are likely starters.
But Feek is not looking for excuses and says he expects the starters, and any potential replacements, to deliver.
Feek said: "All of them need to step up and become leaders in their own right now. We can't wait for someone to do things, we have to stand up and do it.
"Iain Henderson did well off the bench against France [who Ireland defeated on Sunday] and hopefully he can keep his form going.
"I've said before, some games you need guys in from the start, and others for the same guys to make a big impact off the bench. However it falls, they all have to take the game by the scruff of the neck."
The Irish got the better of the French scrum during their 24-9 win last weekend but Feek thinks the Pumas may provide a stiffer test.
"Argentina have come into the World Cup under the radar a bit, but they have got a well-balanced side," he said. "We are under no illusions that this weekend will be our biggest test so far.
"Marcos Ayerza is their big rock, I suppose. Since coming back to the new laws, I think he has come back to the fore, and the World Cup has shown that, if you don't get it quite right, anyone can hit you.
"It's a real mental thing now and with Argentina, they look really good. I think the French were still dangerous, you saw that, but Argentina really know what they want to do and it is going to be a really tough challenge."