Connacht prop Nathan White will make his first Ireland start against South Africa if Mike Ross does not shake off his groin injury.
Head coach Joe Schmidt has confirmed he will draw on New Zealand-born White's Super Rugby experience at tighthead if Ross is sidelined for the 8 November clash.
Former Chiefs and Leinster prop White will become Ireland's fourth oldest debutant of all time at 33 years and 51 days if he faces the Springboks at the Aviva Stadium.
New Zealander Schmidt has promoted White with Marty Moore sidelined after shoulder surgery - and warned of three huge scrummaging challenges ahead next month.
"Nathan White is very experienced. He's played a lot of Super Rugby. He's 33, so he's no spring chicken but his experience is one of the reasons why we have picked him," Schmidt said.
"I'm not sure whether Mike (Ross) will play this weekend or next weekend, because at the moment it's symptom-based.
"If he's able to play then great; if he unavailable for South Africa I think we've got a bit of experience in Nathan and we've got Rodney (Ah You) who has really picked up his form and Steven Archer who is on his way back to form.
"Connacht's two tighthead boys are rewarded for some really good performances - Rodney against Glasgow, Nathan against a number of sides.
"Probably uppermost for Nathan was how we went against Jack McGrath and Cian Healy in the derby game against Leinster.
"To be honest, there aren't too many other options given other injuries. Tadhg Furlong we do believe is a long-term option, but at the moment he's pretty young to be thrown in."
"He's 33, so he's no spring chicken but his experience is one of the reasons why we have picked him."
South Africa ooze scrum power with the likes of Tendai 'Beast' Mtawarira merely the start. Locks Bakkies Botha, Eben Etzebeth and Victor Matfield offer near unrivalled ballast.
Ireland's third autumn opponents Australia may not boast the same set-piece pedigree, but Schmidt warned unfashionable Georgia cannot be overlooked.
Clermont cornerstone Davit Zirakashvili leads the cast, as adept in the wide channels as the dark corners.
Stade Francais prop Davit Kubriashvili and Toulon flanker Mamuka Gorgodze underline Georgia's mammoth pack, leaving Schmidt wary of the fast-improving Lelos.
"We're not just talking about the highly ranked teams. Georgia have got a prop factory," Schmidt said, backing Jack McGrath to cope at loosehead in Cian Healy's absence.
"There are a number of very, very good props, and we don't want to put a guy in a position where he loses a bit of confidence.
"We need to be as solid in that department of the game as we possibly can be.
"On the loosehead side, Jack McGrath has continued to grow and do well for us.
"I think what he did in Argentina was a real benchmark for him.
"Argentina, I know they added (Agustin) Creevy and (Marcos) Ayerza to their front-row but (Ramiro) Herrera was the guy who was starting most of those Rugby Championship matches.
"And he's the guy I felt Jack put a lot of pressure on. So Jack's continued to progress.
"And James Cronin, I thought he came on and did a pretty good job at the weekend.
"And Dave Kilcoyne is the guy who has been there before.
"He came off the bench in the first Test against Argentina and we felt he did a good job.
"So we're trying to benchmark those Test matches and those big European games, or the big PRO12 games - the ones that are either derby games or games against Glasgow or Ospreys."