Tadhg Furlong misses Ireland's Six Nations opener against Wales.
Head coach Andy Farrell revealed that lingering issues with a calf complaint left him without his first-choice tighthead prop.
Finlay Bealham gets the nod in the 3 shirt beside Andrew Porter and Dan Sheehan.
Tadhg Beirne and James Ryan are in the second row.
Peter O'Mahony, Josh van der Flier and Mayo's Caelan Doris make up the back row.
Ulster's Stuart McCloskey starts at inside centre and is partnered by Garry Ringrose.
There's a back three of Hugo Keenan at full back and Mack Hansen and James Lowe on the wings.
Captain Johnny Sexton and Jamison Gibson-Park are in the half-back line.
Bundee Aki is among the replacements for the match in Cardiff on Saturday.
Ireland: Hugo Keenan; Mack Hansen, Garry Ringrose, Stuart McCloskey, James Lowe; Johnny Sexton (capt), Jamison Gibson-Park; Andrew Porter, Dan Sheehan, Finlay Bealham; Tadhg Beirne, James Ryan; Peter O'Mahony, Josh van der Flier, Caelan Doris.
Replacements: Rob Herring, Cian Healy, Tom O'Toole, Iain Henderson, Jack Conan, Conor Murray, Ross Byrne, Bundee Aki.