Caelan Doris will captain Ireland for Sunday's Guinness Six Nations clash against Italy as Andy Farrell makes six changes to his side.
Stuart McCloskey, Craig Casey, Finlay Bealham, James Ryan, Ryan Baird and Jack Conan all come into the starting line-up.
Captain Peter O'Mahony (calf), Tadhg Furlong (calf), Garry Ringrose (shoulder) and Bundee Aki (knee) were all not considered due to injury.
Ireland began the defence of their title with a 38-17 win over France last weekend.
"When I did the press conference after Marseille, I honestly didn't know that we had a few doubts," Farrell told RTÉ Sport.
"It was only until the next morning actually that these were reared up to me.
"So, Peter has got a bit of a calf injury that shouldn’t take too long, but he’s not training at all this week.
"Exactly the same for Tadhg Furlong, he’s not trained at all but we have got a couple of days training next week and they’ll both be expected for that as well, but this was too early.
"He's had a problem with the two [calves] but this is not a serious issue. I'm sure if this was a World Cup final we could try and push him to get onto the field.
"Garry Ringrose is not quite right, needs another week. He's likely to be back into training as well next week."
McCloskey comes in for Aki in the centre, while Casey is preferred over Gibson-Park at scrum-half.
"Bundee has got a rumbling knee that we can continue with this week, but it's going to continue to rumble as well," said the head coach.
"Stuart McCloskey has been going well in training so he deserves a chance and hopefully Bundee will get fit and well in the meantime."
Otherwise the back line is the same with Hugo Keenan at full-back, while Calvin Nash and James Lowe are on the wings.
Robbie Henshaw retains his place alongside McCloskey, who will earn his 16th Irish cap against the Azzurri, beaten 27-24 by England last weekend.
Jack Crowley gets his second Six Nations start at out-half.
Farrell has decided to make four switches to his forward unit with Connacht's Bealham taking the place of Furlong at tighthead. Andrew Porter and Dan Sheehan keep their starting places at loosehead and hooker, respectively.
Ryan is promoted from the bench and partners Joe McCarthy, man of the match in the five-try win over Les Bleus.
Baird and Conan come into the back row.
Doris captains the side from the openside flank on his 38th cap. The 25-year-old Leinster player will become the 110th player to captain Ireland at Test level.
"[It's about] giving people another chance obviously, the lads that took the field last week, to build on that, but also keeping competition in the right places and like I always say, selection takes all sorts," added Farrell.
"All sorts of different permutations go through your mind.
"When you lose a couple of leaders, do you replace them with a leader or somebody that deserves a chance etc?
"Iain Henderson coming onto the bench will help Caelan, I've no doubt, in making sure the changing room feels the way it should be with Pete and Tadhg not being there.
"James Ryan's chomping at the bit to show his worth and start, and big Joe is ready to compete again.
"Then obviously Calvin Nash and Jack get another shot at it.
"Ryan Baird has been playing outstandingly well, he's obviously been very good for us off the bench, to start the game is a different challenge for him.
"Craig Casey has been jumping out of his skin and playing well, and deserves a start.
"So for me, it's a hell of a pack and a good team at that, so it excites me being able to be in that position."
There are also a number of changes to the replacements bench with props Jeremy Loughman and Tom O’Toole included.
Iain Henderson and Josh van der Flier are also on the bench, while Gibson-Park, Harry Byrne and Jordan Larmour are covering the backline.
Meanwhile, Italy have made four changes to the side that were defeated by England in Round 1, as Ange Capuozzo returns to the team.
The full-back missed out on the opener in Rome due to illness, but starts at full-back against Ireland, replacing Tommaso Allan.
Head coach Gonzalo Quesada also makes a change at scrum-half, with Stephen Varney promoted to the starting side at the expense of Alessandro Garbisi.
The other changes are both in the back row and both enforced, with Lorenzo Cannone and Sebastien Negri having been ruled out due to injury.
Alessandro Izekor and Manuel Zuliani come in to start at blindside and openside flanker respectively, while captain Michele Lamaro shifts to number 8.
Ireland: Hugo Keenan; Calvin Nash, Robbie Henshaw, Stuart McCloskey, James Lowe; Jack Crowley, Craig Casey; Andrew Porter, Dan Sheehan, Finlay Bealham; Joe McCarthy, James Ryan; Ryan Baird, Caelan Doris (capt), Jack Conan.
Replacements: Rónan Kelleher, Jeremy Loughman, Tom O’Toole, Iain Henderson, Josh van der Flier, Jamison Gibson-Park, Harry Byrne, Jordan Larmour.
Italy: Ange Capuozzo; Lorenzo Pani, Juan Ignacio Brex, Tommaso Menoncello, Monty Ioane; Paolo Garbisi, Stephen Varney; Danilo Fischetti, Gianmarco Lucchesi, Pietro Ceccarelli; Niccolo Cannone, Federico Ruzza; Alessandro Izekor, Manuel Zuliani, Michele Lamaro (capt).
Replacements: Giacomo Nicotera, Mirco Spagnolo, Giosue Zilocchi, Andrea Zambonin, Ross Vintcent, Martin Page-Relo, Tomasso Allan, Federico Mori.
Listen to the RTÉ Rugby podcast on Apple Podcasts, Spotify or wherever you get your podcasts.
Watch England v Wales in the Guinness Six Nations on Saturday from 4.15pm on RTÉ2 and RTÉ Player
Follow a live blog of Ireland v Italy on Sunday from 2.30pm on rte.ie/sport and the RTÉ News app and listen to live commentary on RTÉ Radio 1
Follow the RTÉ Sport WhatsApp channel for the best news, interviews, analysis and features, as well as details of our sports coverage across all RTÉ platforms
