Wales have returned James Hook to his favoured fly-half role for Saturday's RBS Six Nations fixture with Ireland at the Millennium Stadium.
An injury to Jonathan Davies saw Hook switched to the centre for the 24-16 victory over Italy last time out - but Davies' recovery has facilitated a move back to stand-off.
Davies is fit to reconvene his centre partnership with Jamie Roberts, meaning veteran Stephen Jones, who played fly-half in Rome, drops to the bench.
Leigh Halfpenny is preferred to Morgan Stoddart on the wing in the only other change to the starting XV, which head coach Warren Gatland decided to announce two days earlier than originally planned despite a number of injury niggles in the squad at the start of the week.
Stoddart, a try-scorer against England and Italy this season, has been included among the replacements.
Scrum-half Dwayne Peel is back in the squad among the replacements, where the last two spots will be decided between back-row trio Rob McCusker, Andy Powell and Jonathon Thomas.
Josh Turnbull, Tavis Knoyle and Rhys Priestland, all on the bench at the Stadio Flaminio 10 days ago, have been dropped.
"This is a crucial game for us as a win will keep us in the Championship mix and take us into that final round with everything still to play for," said Gatland, who will break the Wales coaching record of 35 Tests in charge, eclipsing Alan Davies' mark.
"But it is also a big game for Ireland, who are in a similar position to us going into this match."
Addressing the fly-half issue, assistant coach Robin McBryde challenged Hook to justify the faith shown in him.
"The debate at fly-half will continue long after the Championship is over, but we have gone for James on this occasion," McBryde.
"James provides a running threat and we will be looking for him to show he can control the game as well and help us play in the right areas."
Of Halfpenny's recall, McBryde added: "Leigh had a good run out for the Blues at the weekend, we know all about his pace and what he offers around the field as well as being solid under the high ball and giving us a long-range kicking option.
"Morgan misses out, but he has done nothing wrong and we know he can be relied on if we need him from the bench.
"We also have a vast amount of experience in Stephen (Jones) and Dwayne to call upon if necessary. Both have proved in the past that they can come on and make an impact and neither will let us down."
Ireland have only lost once in Cardiff since 1983.
Wales: 15 L Byrne (Ospreys), 14 L Halfpenny (Cardiff Blues), 13 J Roberts (Cardiff Blues), 12 J Davies (Scarlets), 11 S Williams (Ospreys), 10 J Hook (Ospreys), 9 M Phillips (Ospreys); 1 P James (Ospreys), 2 M Rees (Scarlets, capt), 3 C Mitchell (Ospreys), 4 B Davies (Cardiff Blues), 5 A-W Jones (Ospreys), 6 D Lydiate (Newport Gwent Dragons), 7 S Warburton (Cardiff Blues), 8 R Jones (Ospreys)
Replacements: 16 R Hibbard (Ospreys), 17 J Yapp (Cardiff Blues), 18 D Peel (Sale Sharks), 19 S Jones (Scarlets), 20 M Stoddart (Scarlets), plus two from R McCusker (Scarlets), A Powell (Wasps) and J Thomas (Ospreys)