Robbie Henshaw has been ruled out of Ireland's World Cup clash with Scotland through injury, while Dan Sheehan and Iain Henderson start for Andy Farrell's side.
Jack Conan is in line for his first taste of tournament action after being named on the bench the Pool B match in Paris on Saturday (8pm).
The Lions number 8 had been sidelined with a foot injury since the start of August but is set to feature at Stade de France.
Henderson gets in ahead of James Ryan in the second row, with the Leinster player starting on the bench.
"He's fit and he had a bit of a niggle on a wrist but that’s fine," said head coach Andy Farrell about Ryan (above).
"He’s fit and raring to go."
Elsewhere, hooker Sheehan starts with Rónan Kelleher named among the replacements.
Henderson and Sheehan's inclusion mean there are just two changes to the team that beat South Africa 12 days ago.
There was bad news, however, for Leinster centre Henshaw, who suffered a hamstring injury on Tuesday and faces at least a couple of weeks out.
"He pulled up with a hamstring at the end of the session on Tuesday, unfortunate for him," said Farrell.
"The diagnosis with hamstrings, they want to see how things settle down it probably takes around five days for that kind of thing to happen.
"It looks like it could be a minimum of a couple of weeks at this stage."
Stuart McCloskey also makes his first match-day squad of the tournament with the Ulster centre among the substitutes.
Andrew Porter and Tadhg Furlong start either side of Sheehan, with Tadhg Beirne retained in the second row.
The back row also remains unchanged with Peter O’Mahony set to win his 100th Ireland cap on the flank. The Munster skipper will be alongside Josh van der Flier and number 8 Caelan Doris.
As expected, the starting backline is the same with Jamison Gibson-Park linking up with captain Johnny Sexton in the half-backs.
Man of the match in the last two games Bundee Aki again partners Garry Ringrose in midfield.
Hugo Keenan starts at full-back, with Mack Hansen and James Lowe on the wings.
Ireland will qualify for the knock-out stages with a win or a draw, while a series of other results could see them progress. Defeat by eight points or more without getting a try bonus point would see Ireland crash out.
Scotland have not beaten Ireland in eight games stretching back to 2017.
Ireland: Hugo Keenan; Mack Hansen, Garry Ringrose, Bundee Aki, James Lowe; Johnny Sexton (capt), Jamison Gibson-Park; Andrew Porter, Dan Sheehan, Tadhg Furlong; Tadhg Beirne, Iain Henderson; Peter O'Mahony, Josh van der Flier, Caelan Doris.
Replacements: Rónan Kelleher, Dave Kilcoyne, Finlay Bealham, James Ryan, Jack Conan, Conor Murray, Jack Crowley, Stuart McCloskey.
Scotland: Blair Kinghorn; Darcy Graham, Huw Jones, Sione Tuipulotu, Duhan van der Merwe; Finn Russell, Ali Price; Pierre Schoeman, George Turner, Zander Fagerson; Richie Gray, Grant Gilchrist; Jamie Ritchie (capt), Rory Darge, Jack Dempsey.
Replacements: Ewan Ashman, Rory Sutherland, WP Nel, Scott Cummings, Matt Fagerson, Luke Crosbie, George Horne, Ollie Smith.
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