Andy Farrell admits Ireland's squad depth will be severely tested after captain Johnny Sexton was among a host of senior players ruled out of Sunday's must-win Guinness Six Nations clash with France.
Fly-half Sexton and vice-captain James Ryan have failed head injury assessments, while scrum-half Conor Murray has sustained a hamstring problem and Peter O'Mahony is suspended.
The enforced absences have resulted in Farrell naming an inexperienced half-back pairing of Billy Burns and Jamison Gibson-Park, ending Rhys Ruddock's international exile, and handing the armband to recalled lock Iain Henderson.
Ireland have to beat the French to keep alive their title hopes and, despite a week of serious disruption, head coach Farrell remains upbeat about his contingency plans.
"We're excited about it. We've obviously lost a few experienced players during the week but one man's loss is another man's opportunity," he said.
"The squad is united in the excitement of the challenge ahead for the weekend.
"You have your fingers crossed along the way that things don't go this way, but that's why you pick a squad like you do in the autumn and give people a chance to see what it's like at international rugby.
"Our squad depth is coming into play at this moment in time.
"It's been challenging, but every Test week always presents its own challenges.
"There has been a lot going on this week but we're a squad and we've been a squad since we met up. Everyone has been swapping in and out.
"You always have at the back of your mind the 'what if' scenarios and here we are. We will give it our best shot, there is no doubt about that."
Sexton and Ryan each suffered head injuries during the 21-16 loss to Wales and were unable to satisfy return-to-play protocols, while Murray was ruled out just before Farrell named his team on Friday afternoon.
Flanker O'Mahony was hit with a three-match ban earlier this week after a costly 14th-minute red card in Cardiff.
His suspension means Leinster man Ruddock will come into the back row for his first Ireland appearance since coming off the bench in the 2019 World Cup quarter-final defeat to New Zealand.
Burns, meanwhile, has been trusted with filling the sizeable boots of Sexton despite a costly late error against Wayne Pivac's men.
Farrell has backed the Ulster player – who has won just four caps – to bounce back from missing touch with a penalty in the final seconds of their opening-weekend defeat.
"He's been great. He's strong, Billy. He's a proper footballer," said Farrell.
"Everyone makes mistakes and, at international rugby, he understands the extent of that.
"But he's a true professional, his team are right behind him, and he's trained outstandingly this week.
"We've had plenty of conversations, like I do with the rest of the team. You always try and help them find the reasons why and the process that they have been through, and see how they are able to cope and park and move on.
"Come Tuesday, Billy has been absolutely fine."
Ulster skipper Henderson, who came off the bench in Cardiff following a knee problem sustained in the final game of the Autumn Nations Cup, becomes the 108th player to captain Ireland.
Speaking about that decision, Farrell said: "He brings authority. He also brings a calmness.
"I think that was one of the really pleasing aspects of the weekend against Wales regarding going down to 14 men, there was a calmness throughout the leadership group and Iain was right, front and centre of all of that.
"He'll do exactly the same, he will see it as a challenge, he will get excited about it and I am sure he will lead the boys very well."
Absent skipper Sexton was upset earlier in the week about claims made by French doctor Jean-Francois Chermann that he had suffered "around 30 concussions" during his career.
Dr Chermann, who treated the 35-year-old during his time with French club Racing 92, later apologised and retracted his remarks but Farrell was also angered by the episode.
"Honestly, I thought it stunk, on so many grounds. I suppose I will leave it at that," said the head coach.
