Munster Academy member Alex Wootton, who makes his first appearance of the tournament, has been named on the left wing with Ian Fitzpatrick making way.
Up front, Darragh Moloney, who joins the Munster Academy for next season, is named in the second row where he partners Ross Molony.
Josh Murphy and Harrison Brewer are two new additions on the replacements bench, with both players having lined out in the Ireland Under-19s' home win over France in April.
Friday's clash with Wales is a 'must win' game for Ruddock's charges, who are currently third in Pool B - with one losing bonus point - behind France (4 points) and the table-topping Welsh (5).
There will be live coverage of the Ireland v Wales encounter from Pukekohe on TG4 and Sky Sports 1 (red button) (kick-off 5.35pm local time/6.35am Irish time).
IRELAND UNDER-20 Team & Replacements (v Wales Under-20s, 2014 IRB Junior World Championship - Pool B, ECOLight Stadium, Pukekohe, New Zealand, Friday, June 6, kick-off 5.35pm local time/6.35am Irish time):
15. Cian Kelleher (Lansdowne/Leinster)
14. Ciaran Gaffney (Galwegians/Connacht)
13. Garry Ringrose (UCD/Leinster)
12. Dan Goggin (Young Munster/Munster)
11. Alex Wootton (Garryowen/Munster)
10. Ross Byrne (UCD/Leinster)
9. Nick McCarthy (UCD/Leinster)
1. Peter Dooley (Lansdowne/Leinster)
2. Max Abbott (Cork Constitution/Munster)
3. Rory Burke (Cork Constitution/Munster)
4. Darragh Moloney (Cork Constitution/Munster)
6. Peadar Timmins (UCD/Leinster)
7. Frankie Taggart (Belfast Harlequins/Ulster)
8. Jack O'Donoghue (UL Bohemians/Munster) (capt)
16. Dylan Donnellan (UCD/Leinster)
17. Denis Coulson (Lansdowne/Leinster)
18. Oisin Heffernan (Lansdowne/Leinster)
19. Josh Murphy (UCD/Leinster)
20. Diarmaid Dee (Young Munster/Munster)
21. Ryan Foley (Cork Constitution/Munster)
22. Conor McKeon (Lansdowne/Leinster)
23. Harrison Brewer (Terenure College/Leinster)
IRELAND - POOL B FIXTURES/RESULTS:
Monday, June 2: France 19 IRELAND 13, QBE Stadium, Auckland
Friday, June 6: Wales v IRELAND, ECOLight Stadium, Pukekohe, 5.35pm local time/6.35am Irish time (live TG4/Sky Sports 1, red button) (Buy match tickets)
Tuesday, June 10: IRELAND v Fiji, QBE Stadium, Auckland, 1.35pm local time/2.35am Irish time (live TG4) (Buy match tickets)
For the full fixtures list, please click here.