Mike Phillips has been preferred to Dwayne Peel at scrum-half as one of four changes made by Wales head coach Warren Gatland.
The other three all come in the pack, with Alun-Wyn Jones restored to the second row in place of Ian Evans after recovering from an ankle injury suffered in the win over England.
Huw Bennett returns at hooker with the chief task of steadying the Wales lineout, which malfunctioned against Italy, while prop Adam Jones regains the tight-head role from Rhys Thomas.
Gatland said: "A number of players have had a run-out for us in the first three games of the championship and selection in most areas could be put down to the toss of a coin, which is testament to the effort the guys have put in.
"We've had to make a judgement call at scrum-half, in the front row and in the second row, but it really is a close call for us in each of those positions as well as elsewhere in the team."
Gatland has already identified Ronan O'Gara as Ireland's chief threat and he will look at Jones to wrest control away from the Munsterman.
"In Ronan O'Gara they have someone who can direct the game and really hurt opponents. If we don't keep a tight rein on him it could be a long day for us. We will be showing Ronan and his side the utmost respect," said Gatland.
Wales head to Dublin as the only unbeaten side in the competition and top of the Six Nations table after wins over England, Scotland and Italy.
But any one of four teams can still win the title and Gatland insisted: "We go there as underdogs.
"Ireland are a fantastic side, they've been a top-five team in world rugby for a number of years.
"They have lost only one game themselves, in the dying minutes against France, and Croke Park will be an intimidating place, but we must not be daunted by the task at hand.
"You only have to look at the number of caps they have throughout the side to recognise they will be a major force to be reckoned with.
"We are in a great position going for the Triple Crown. It would be nice, but the most important thing to us is the championship."