An injury to Robbie Henshaw has obliged Ireland head coach Joe Schmidt to select an inexperienced centre pairing for Saturday's Test against Argentina at Lansdowne Road.
Bundee Aki and Chris Farrell, boasting just two caps between them, will line-up as the Irish seek to make it three wins from three November Tests after Henshaw suffered a suspected hamstring injury this week.
Schmidt gives Leinster wing Adam Byrne his Test debut, after a breakthrough season last year ending a nightmare run of injuries which had seen him break a leg twice, against a Pumas side that destroyed Irish World Cup hopes in the 2015 quarter-finals.
Schmidt told Thursday's press conference: "Robbie Henshaw has a slight hamstring injury and potentially could have been involved but has a busy period coming up so we decided to not risk him.
"Chris (Farrell) acquitted himself pretty well last weekend against Fiji and we will see how he measures up against Pumas."
Turning to Byrne he commented: "Byrne gave us confidence with his work in training camp to include him.
"He has worked really hard picking things up all the time and with a bit of experience around him in the backs really hoping he gets a good work out for him in his first time in Irish jersey."
As expected Schmidt -- who gave 23-year-old Byrne his debut when he was head coach at Leinster -- has reverted to largely the starting XV that romped to a record 38-3 victory over South Africa a fortnight ago -- having fielded an inexperienced side in the 23-20 win over Fiji last Saturday.
Wing Andrew Conway and lock Devin Toner who are the only two to have started the two previous Tests are on the replacements bench allowing Byrne to get his blooding and 21-year-old Leinster team-mate James Ryan to get a first Test start.
Five of the starting XV who were beaten 43-20 by the Argentinians in 2015 remain including fullback Rob Kearney, who wins his 78th cap.
Ireland's British and Irish Lions half-back partnership of scrum-half Conor Murray and Johnny Sexton -- the latter was injured and missed the quarter-final defeat -- are also reunited after being rested for the Fiji game.
The Irish will start as warm favourites with the Pumas having tasted victory just twice this year, their win over Six Nations whipping boys Italy last Saturday ending a seven match losing run.
Pumas head coach Daniel Hourcade made three changes to that starting line-up chief of which was dropping veteran No8 Juan Manuel Leguizamon to the bench and bringing in Tomas Lezana to replace him.
Rob Kearney; Adam Byrne, Chris Farrell, Bundee Aki, Jacob Stockdale; Johnny Sexton, Conor Murray; CJ Stander, Sean O'Brien, Peter O'Mahony; Iain Henderson, James Ryan; Tadhg Furlong, Rory Best (capt), Cian Healy
Replacements (16-23): James Tracy, Dave Kilcoyne, John Ryan, Devin Toner, Rhys Ruddock, Luke McGrath, Ian Keatley, Andrew Conway
Coach: Joe Schmidt (NZL)
Joaquin Tuculet; Ramiro Moyano, Matias Moroni, Santiago Gonzalez Iglesias, Emiliano Boffelli; Nicolas Sanchez, Martin Landajo; Tomas Lezana, Marcos Kremer, Pablo Matera; Tomas Lavanini, Matias Alemanno; Nahuel Tetaz Chapparo, Agustin Creevy (capt), Santiago Garcia Botta
Replacements (16-23): Julian Montoya, Lucas Noguera, Enrique Pierretto, Guido Petti, Juan Manuel Leguizamon, Gonzalo Bertranou, Jeronimo de la Fuente, Sebastian Cancelliere
Coach: Daniel Hourcade (ARG)