Commenting on the selection call at full-back, Kidney said: "Geordan (Murphy) was playing well all last season I thought. He had been injured for quite some time and answered the call last time out against England.
"I thought he was unlucky in about game four of last year's Six Nations not to get the nod again, and I thought he played well enough against England to warrant giving him a second test.
"Rob has worked really hard at getting back in, it's not like he has done anything wrong. But I've just sided with Geordan on this one."
He added: "(At number 10) I'm sure everybody is going to be talking about 10. That is I wouldn't say a welcome difficulty, but I said it before that we are fortunate to have two great 10s and I think that's what we have.
"There are other players too, I think Andrew was very unlucky to lose out on this one because he has done very well every time he has come in.
"Paddy Wallace has been exceptional within the squad and I couldn't speak highly enough of him and about the way he has gone about doing his work.
"Paddy would just epitomise the work that is going on with a lot of other guys. I think just to really break it down to the difficulty of two positions would not recognise the work that is being done by all of the other members in trying to make the squad.
"Because right through, Marcus (Horan) has been pushing hard, Tom Court has been unlucky and there's quite a number of fellas like that."
Click here to view the selected Wales team, captained by flanker Martyn Williams.
IRELAND Team & Replacements (v Wales, 2010 RBS 6 Nations Championship, Croke Park, Saturday, March 13, kick-off 2.30pm):
15 - Geordan Murphy (Leicester Tigers)
14 - Tommy Bowe (Ospreys)
13 - Brian O'Driscoll (UCD/Leinster) (capt)
16 - Sean Cronin (Buccaneers/Connacht)
17 - Tony Buckley (Shannon/Munster)
18 - Leo Cullen (Blackrock College/Leinster)
19 - Shane Jennings (St. Mary's College/Leinster)
20 - Eoin Reddan (Lansdowne/Leinster)
21 - Ronan O'Gara (Cork Constitution/Munster)
22 - Rob Kearney (UCD/Leinster)