Captain Dan Sheehan is out with concussion and replaced at hooker by Ronan Kelleher with lock Tadhg Beirne taking over as skipper.
Jamison Gibson-Park is restored to scrumhalf after Craig Casey started last week against Argentina.
Sean Jansen's injury means a reshuffle of the loose forwards with Nick Timoney moving to number eight and Josh van der Flier coming in on the flank.
James Ryan is promoted from the bench to take the place of Joe McCarthy in the second row.
The centre pairing has been changed with Bundee Aki, named among the replacements a week ago before being withdrawn due to illness, forming a new midfield partnership with Jamie Osborne, who was called up in Aki's absence.
Mack Hansen, who was on the wing for the 42-12 victory last Friday, is selected to start at fullback. Hugo Keenan is rested and Tommy O'Brien comes in on the left wing.
Ireland team:
Starters: 15-Mack Hansen, 14-Rob Baloucoune, 13-Jamie Osborne, 12-Bundee Aki, 11-Tommy O’Brien, 10-Sam Prendergast, 9-Jamison Gibson-Park, 8-Nick Timoney, 7-Josh van der Flier, 6-Ryan Baird, 5-Tadhg Beirne (captain), 4-James Ryan, 3-Tadhg Furlong, 2-Ronan Kelleher, 1-Andrew Porter
Replacements: 16-Tom Stewart, 17-Tom O'Toole, 18-Sam Illo, 19-Darragh Murray, 20-James McNabney, 21-Craig Casey, 22-Ciaran Frawley, 23-Stuart McCloskey
Fiji team:
Starters: 15-Ponipate Loganimasi, 14-Selestino Ravutaumada, 13-Setareki Bituniyata, 12-Josua Tuisova, 11-Jiuta Wainiqolo, 10-Ben Volavola, 9-Frank Lomani, 8-Peceli Yato (captain), 7-Lekima Tagitagivalu, 6-Mesake Vocevoce, 5-Isoa Nasilasila, 4-Joseva Tamani, 3-Luke Tagi, 2-Tevita Ikanivere, 1-Peni Ravai
Replacements: 16-Zuriel Togiatama, 17-Vilikesa Nairau, 18-Inoke Ravuiwasa, 19-Kitione Salawa, 20-Elia Canakaivata, 21-Terio Tamani, 22-Caleb Muntz, 23-Iosefo Masi.