Johnny Sexton has missed out on Ireland's World Cup warm-up clash with England at Twickenham on Saturday.
The British and Irish Lions fly-half sat out training at the start of the week in Ireland's warm-weather camp in Portugal.
The Leinster playmaker has been recovering from a thumb sprain but Ireland had hoped he would be ready to feature against England.
Ross Byrne will start at fly-half and has a big chance to state his case for World Cup selection, with Joey Carbery's ankle ligament problem threatening to rule him out of the tournament in Japan.
Ireland have rolled out most of their big guns to face England, with Rory Best back as captain in a potent pack including the first-choice back-row of Peter O'Mahony, Josh Van Der Flier and CJ Stander.
Jean Kleyn wins his second cap at lock, the South Africa-born Munster star handed another chance to prove his World Cup worth.
— Irish Rugby (@IrishRugby) August 22, 2019
Ireland team to play England
Forwards: 1 Cian Healy (Leinster), 2 Rory Best (CAPTAIN, Ulster), 3 Tadhg Furlong (Leinster), 4 Iain Henderson (Ulster), 5 Jean Kleyn (Munster), 6 Peter O'Mahony (Munster), 7 Josh van der Flier (Leinster), 8 CJ Stander (Munster)
Backs: 9 Conor Murray (Munster), 10 Ross Byrne (Leinster), 11 Jacob Stockdale (Ulster), 12 Bundee Aki (Connacht), 13 Garry Ringrose (Leinster), 14 Larmour (Leinster), 15 Rob Kearney (Leinster)
Replacements: 16 Sean Cronin (Leinster), 17 Jack McGrath (Leinster), 18 Andrew Porter (Leinster), 19 Devin Toner (Leinster), 20 Tadhg Beirne (Munster), 21 Luke McGrath (Leinster), 22 Jack Carty (Connacht), 23 Andrew Conway (Munster)