Andrew Porter will have to fill the sizeable boots of British and Irish Lions star Tadgh Furlong when he makes his first Six Nations start against Wales at Lansdowne Road on Saturday.
The 22-year-old, a relative novice at tighthead prop, impressed against Italy after Furlong had to go off in the fourth minute with a hamstring problem and will be joined by centre Chris Farrell, who comes in for the injured Robbie Henshaw, in making their first Six Nations starts.
Other changes from the starting XV that thrashed Italy 56-19 to make it two wins from two see CJ Stander return at No 8 instead of Jack Conan, James Ryan replace the injured Iain Henderson in the second row, and veteran prop Cian Healy come in for Jack McGrath.
"Tadgh was close but we decided not to risk him and to wait for the Scotland match in a fortnight," said Ireland head coach Joe Schmidt.
"Andrew (Porter) did a sterling job against Italy and acquitted himself really well. This will be a step up but it is a learning process for him and nowhere else better to do so than against a tough team like Wales."
Porter, who will win his fifth cap since his debut against the United States last year, began life as a loosehead prop but switched to tighthead for his province Leinster just last term.
The 76 minutes the hulking Porter (120kg, 18st 12lbs) played against Italy is the most he has spent on the pitch in any game since he broke through into the Leinster first team last season.
- Farrell, Aki pairing -
Farrell, who only made his debut against Fiji last November, will form an inexperienced partnership in the centres with Bundee Aki, although the latter sparkled in the Italy match as the New Zealand-born back scored his first try for his adopted country while setting up another.
"Losing three world class players is tough (Henderson, Henshaw and Furlong) but we are focused on those who are playing," said Schmidt.
"Chris Farrell has been a long-term project. We are short on experience, they are welcoming back three Lions while we are losing three. Not ideal but nowhere better to carry on the learning curve."
Ryan sat out the Italy game with a niggle he picked up in his impressive Six Nations debut against France and will be alongside Leinster team-mate Devin Toner.
Schmidt has omitted Jordan Larmour completely from the matchday 23, the talented 20-year-old perhaps paying the price for missing tackles in two of Italy's tries after coming on for his Test debut. The more battle-hardened Fergus McFadden takes his spot on the replacements bench.
The hard core of experience in the side, which will be needed against a Wales outfit who are unfortunate not to be unbeaten themselves, is there with Rory Best skippering them in his 109th Test for his country, and the world class half-back pairing of Johnny Sexton and Conor Murray once again pulling the strings.
Schmidt has not lost a home Six Nations match since assuming the reins after the 2013 edition although the Welsh came close to beating the Irish in a 16-16 draw in 2016.
Rob Kearney; Keith Earls, Chris Farrell, Bundee Aki, Jacob Stockdale; Johnny Sexton, Conor Murray; CJ Stander, Dan Leavy, Peter O'Mahony; Devin Toner, James Ryan; Andrew Porter, Rory Best (capt), Cian Healy
Replacements: Sean Cronin, Jack McGrath, John Ryan, Quinn Roux, Jack Conan, Kieran Marmion, Joey Carbery, Fergus McFadden
Coach: Joe Schmidt (NZL)