• Rory Lawson
The alterations see Rory Lawson replace the injured Chris Cusiter at scrum-half and Moray Low come in at tight-head prop for the recuperating Euan Murray.
It will only be Lawson's second start as he wins his 19th cap, his first start having occurred against France in Paris three years ago.
However, the 29-year-old has consistently won plaudits from head coach Andy Robinson – most notably for the major part he played in steering Scotland home to a win against the Wallabies at Murrayfield last November –and is determined to seize his chance.
Robinson explained: "Rory has performed well for Gloucester at the end of the season.
"You have to view this on merit. I think we have three outstanding scrum-halves and I believe it's right to pick Rory. Mike (Blair) is a quality performer.
"He will still have an influence on the game at the weekend."
In last November's match against Australia, Alastair Kellock took over the captaincy just as Lawson assumed responsibility at scrum-half, so, fittingly, Kellock – who first toured with Lawson in the Scottish Schools party to New Zealand in 1999 – leads the Scotland team for the first time from the outset on Saturday.
"I expect Al to lead from the front as he has done with his performances this year for Scotland," declared Robinson.
Kellock, who skippered Glasgow Warriors to the inaugural Magners League play-offs this season, thus becomes Scotland's 110th Test match captain and he is relishing taking on an Argentinian pack brimful of world-class performers in what Robinson described as the "bear pit" of Tucuman.
"It's like opposition teams coming to Firhill – they must feel the same," Kellock said.
While 13 of the starting XV against Ireland will take to the field in Tucuman, there are only three survivors on the bench – Scott Lawson and the Edinburgh half-backs Phil Godman and, Scotland's most-capped scrum-half of all time, Mike Blair.
Introduced to the match-day 22 are Edinburgh forwards Geoff Cross and Scott MacLeod – the latter last played a cap Test match for Scotland on the corresponding visit to Argentina two years ago – Gloucester's blindside flanker Alasdair Strokosch; and, the only uncapped member of the squad, Edinburgh's resourceful back, Jim Thompson.
Thompson, 25, who was playing in the club international side just three years ago, joins his cousin, Rory Lawson, in the squad and is one of four Dollar Academicals (alongside Lawson, Graeme Morrison and John Barclay) in the match 22 – a remarkable achievement for the Clackmannanshire school.
As grandsons of the late and much revered 'Voice of Rugby', Bill McLaren, Lawson and Thompson have endured a traumatic year following the passing away of a rugby legend.
Thompson reflected: "Papa always said if he could have changed one thing it would have been to win one Scotland cap. I know how much it would mean to me and it would mean a lot for him and the family."