Rob Kearney and Keith Earls have been ruled out of Ireland's World Cup opener against Scotland on Sunday (kick-off 8.45am) with Andrew Conway and Jordan Larmour named to start in Yokohama.
Andy Farrell insisted that the experienced Irish pair "ran well" on Wednesday in training, but there had been doubts all week over their fitness, with Kearney (calf) and Earls (thigh) replaced by Andrew Conway and Jordan Larmour respectively.
Conway, who has shown his versatility in the backline, comes in for his 16th cap, which is one less than Leinster tyro Larmour (below).
"It was just that we were getting very tight for time, the best continuity we had was we felt was to have the guys who trained through the time that we've been here, it's exciting to have the back three that we have," head coach Joe Schmidt told RTÉ Sport this morning.
"In the backs, only Robbie Henshaw is not available.
"I think everyone else could play. Keith has hit some really good speeds in training on Wednesday, Rob Kearney will be ready to train today and Joey Carbery has trained throughout the week but they are all playing a little bit of catch-up.
"The problem is if you put them in, and you've got a tournament like this, they are a little bit underdone, then you’ve got a risk that you potentially cause another injury, we don’t want to take that risk. It's early in the tournament."
The back three is completed by Jacob Stockdale.
Schmidt added of Larmour and Conway: "I think that their enthusiasm is something that's contagious, their ability to get themselves into the game.
"Andrew has proven aerial ability and that will be really useful for us.
"I still have the vision very clearly in my mind of Jordan Larmour beating Israel Folau to a ball in the third Test in Sydney on our Australian tour last year.
"So he's very good there as well, and of course Jacob is a big man in the back-field.
"They're all feeding off each other, they are all very, very keen to impress. And now they have that opportunity."
With Henshaw also unavailable, Bundee Aki is partnered by Garry Ringrose in midfield with the first choice half-backs of Jonathan Sexton and Conor Murray.
Captain Rory Best is flanked in the front row by Cian Healy and Tadhg Furlong, with James Ryan and Iain Henderson in the engine room.
The back row is made up of Peter O'Mahony, Josh van der Flier and CJ Stander.
He added: "Up front there were some tight decisions as well.
"Whether a player starts or comes off the bench they are very important to us, we need the right people coming off the bench doing the right job."
Joey Carbery, who only returned to full training this week following an ankle injury is not included in the squad.
Ireland: Jordan Larmour; Andrew Conway, Garry Ringrose, Bundee Aki, Jacob Stockdale; Jonathan Sexton, Conor Murray; Cian Healy, Rory Best (capt), Tadhg Furlong; James Ryan, Iain Henderson; Peter O’Mahony, Josh van der Flier, CJ Stander.
Replacements: Niall Scannell, Dave Kilcoyne Andrew Porter, Tadhg Beirne, Jack Conan, Luke McGrath, Jack Carty, Chris Farrell
Follow Ireland v Scotland on Sunday (kick-off 8.45am) via the live blog on RTÉ.ie/Sport and the News Now App, watch live on RTÉ2 from 8am or listen to live match commentary on RTÉ Radio 1.