British Lions Stephen Jones and Matthew Rees are in the Scarlets squad which plays European champions Munster in Cork tomorrow (Friday).
They are due to start on the bench, with Jones set to win his battle with a hamstring difficulty that saw him miss last Saturday's home game with the Ospreys. Rhys Priestland, aged 22, keeps the 10 jersey after impressing against the Ospreys.
Hooker Rees played the full 80 minutes against the Scarlets' West Wales neighbours. Fellow Welsh international Mark Jones retains the captaincy this weekend, with Sevens World Cup champion Lee Williams keeping his place on the opposite wing.
Prop Deacon Manu is out with an Achilles sprain, backrow Dafydd Jones with a rib cartilage knock. They're replaced by former Cardiff Blues and Wales U21 tighthead Scott Roberts, who makes his Scarlets Magners League debut following a friendly appearance at the Dragons on March 26, and 23-year-old flanker Rob McCusker.
The bench includes flanker Johnny Edwards, back from a three-month injury lay-off and development contract lock Aaron Shingler.
Scarlets head coach Nigel Davies said: "Munster will be a big challenge for us but I'm confident that we can do ourselves justice.
"Our team stood up really well against the Ospreys. We had a lot of young boys out there and we'd had disruptions through the week due to injuries but we fronted up to the challenge.
"In many ways, I was delighted because what we're starting to see now is the advance of a lot of our younger players, the players who'll form a bedrock for the future of this region.
"The fact that they're being exposed to experiences such as the Ospreys and Munster mean that they'll be in a very strong position as we move forward."
Injured personnel include: Darren Daniel (leg), Simon Easterby (knee), Gavin Evans (calf), Regan King (hamstring), Kees Meeuws (Achilles), Morgan Stoddart (knee).
Munster (away - Musgrave Park, Cork), Friday April 24, 7.35pm
15 Daniel Evans, 14 Mark Jones (c), 13 Rob Higgitt, 12 Jon Davies, 11 Lee Williams, 10 Rhys Priestland, 9 Martin Roberts, 1 Iestyn Thomas, 2 Mahonri Schwalger, 3 Scott Roberts, 4 Vernon Cooper, 5 Dominic Day, 6 Josh Turnbull, 7 Rob McCusker, 8 David Lyons.
Reps - 16 Phil John, 17 Matthew Rees, 18 Aaron Shingler, 19 Johnathon Edwards, 20 Gavin Cattle, 21 Stephen Jones, 22 Ceiron Thomas.
Nearly 40 players were involved in the first Wales Under 18 training session of the season. WRU National Performance Manager Gethin Watts is excited at the potential shown by the group and expects the Regional Under 18 Championship to hone their skills even further.