The 19-year-old took a 15-hour flight from Argentina, where he was captaining the Under-20s at the IRB Junior World Championship, and has been quietly going about his business all week as he gears up to face a Maori back row containing two All Blacks in Liam Messam and Tanerau Latimer.
Ruddock played three Magners League games for Leinster this past season and skippered the Ireland Under-20s to the Six Nations title following four wins out of five.
Given his consultancy work with Leinster, Ireland backs Alan Gaffney has seen the teenage flanker at close quarters, at training and in match situations, and believes he has what it takes to make it in the senior ranks.
"It's a fantastic experience for Rhys. I think he's an exceptional player. He's only played so many games in the Magners League but he's shown a nick skill level and a high level of intensity," said Gaffney.
"He's probably got that from his father, he comes from pretty good stock. He's a tough boy, a very, very skilful boy and has got all the attributes to make it in the professional game and at the highest level."
Rhys is, of course, the son of former Leinster and Wales Grand Slam-winning coach Mike Ruddock, and the family affair continues with his older brother, former Ireland Under-20 lock Ciaran, working alongside him in the Leinster Academy.
One of the key aims for Rhys, Niall Ronan and Chris Henry at Rotorua International Stadium will be to make sure Ireland have a plentiful supply of ball, as this much-changed team looks to continue the good work of Brian O'Driscoll and company in the second half of last weekend's Test.
"So I think we now have more of an understanding that we do have to keep the ball in hand and we do have to attack the sides more.
'"We haven't gone from being a very good side to being a poor side overnight. We've just got to understand the fact that we are a good side and back ourselves accordingly.
"The new interpretations allow us to play and allow us to control the ball and play it at pace. Once we become accustomed to that, I think we're going to become quite a force to be reckoned with."
New Zealand Maori kickstarted their centenary season with a 37-31 win over the New Zealand Barbarians last Saturday in Whangarei, and have ventured to Rotorua determined to remain on the winning trail.
Coached by Jamie Joseph and Daryl Gibson, the Maori selection boasts power and pace but Gaffney feels the chosen Ireland side, which includes four uncapped players, will also bring that mix to the table.
"The Maori have a very, very strong team. You look at their backs - (Stephen) Brett, (Luke) McAlister - and in the forwards - Messam, Latimer, Corey Flynn - they are a very, very strong team.
"So it's not as though they are guys put out to pasture. And mixing them with a lot of young guys will make it a very difficult game on Friday.
"And it's good because we have the same mix-up. We have a lot of experience with a lot of young guys and it's going to be a great challenge for them."