Porter the youngest of many fresh-faced Irish internationals
Ireland captain Rhys Ruddock has guaranteed there "will be no complacency" against Fiji.
How could there be in this set of circumstances?
This is Ireland's second fifteen, more or less, containing one man making his debut, in centre Chris Farrell, and three more starting for the first time, in Rob Herring, wing Darren Sweetnam and prop Andrew Porter. Further to that, more than half of the team has five caps, or under, with four of the reserves holding the same experience.
Fiji coach John McKee has centred his selection around seven magnificent men from France's Top-14 and three from England's Premiership.
He has withheld Clermont-Auvergne's explosive Peceli Yato and Glasgow's Nikola Matawalu and Newcastle's Vereniki Gonevea as bench-warmers for an impressive late impact.
To prevent leakages out wide, Ireland have to cut off Fiji's supply at source.
This is where the front five's domination can cause the guests to grow impatient and indisciplined. Twenty-one-year-old Leinster tight-head Porter has had just one start this season against the Southern Kings.
He has not broken into the Champions Cup squad yet and came off the bench for his two Ireland caps in the summer.
Something of an athletic freak, the St Andrew's College graduate has to do what Tadhg Furlong did before him.
He has to nail down the core duties of his position at the set-piece, scrum and lineout, in the maul, hammer into rucks and not be exposed in defence. "I think it speaks volumes for him that he only really moved to tight-head a year ago," marvelled Ruddock.
"He's now where he is, and going to be starting against Fiji at tight-head. That sort of displays the work ethic and the sort of willingness to want to learn.
"I don't know many people who could make that transition so quickly, and I know his physical ability will affect that."
The rookie international is not exactly surrounded by a wealth of experience in the front row where Ulster's Herring will also make his first start.
However, the presence of Leinster colleagues Jack McGrath and Devin Toner allied to an all-Blue back row of Ruddock, Jordi Murphy and Jack Conan will make for many familiar faces.
Flanker Ruddock was cautiously optimistic at the Captain's Run yesterday. "We're well aware that this is a huge test," he said, "both in terms of maybe the limited experience we have on our side and the lack of time with the combinations and the ability of the opposition.
"If we let them play the way they want to play they're capable of beating any team," added Ruddock. "It's a massive test."