Brian O'Driscoll will continue his role as caretaker captain when Ireland face Fiji at Lansdowne Road this Sunday.
The 23-year-old O'Driscoll led his country for the first time last weekend in the absence of the injured hooker Keith Wood and inspired the Irish to a rousing victory in the rain over the world champions Australia in Dublin.
The Lions centre was expected to hand over the captaincy this weekend as he and several other front-line players were rested before the game with Argentina on Saturday week. But a knee injury to the Munster wing John Kelly has scuppered those plans and O'Driscoll is back to lead a side showing nine changes from the side that beat the Wallabies.
David Humphreys replaces Ronan O'Gara at fly-half and the Ulsterman will win his 47th cap, eclipsing the record for an Irish No10 set by another Ulsterman, Jack Kyle, between 1947 and 1957.
Humphreys is partnered by Guy Easterby at scrum-half, Justin Bishop of London Irish starts on the wing and Leicester's Geordan Murphy replaces Girvan Dempsey at full-back.
There are more changes in the forwards, who include an all-Munster front row with the prop Marcus Horan and the hooker Frankie Sheahan joining John Hayes, and Leo Cullen renews his Leinster second-row alliance with Malcolm O'Kelly. The London Irish flanker Kieron Dawson returns after a 12-month absence.
Ireland's coach Eddie O'Sullivan believes that, with the potentially tougher assignment against the rugged Argentina pack to come, some of his key men need a rest.
He said: "It is a big ask to play three games of such importance in quick succession but it should be good for us. We go to Australia for the World Cup and will have to play at least four times in four weeks.
"We have been trying to protect players from burn-out, although this country is better than some others. I don't expect any of our top players to have made more than 14 representative appearances before Christmas."
The Ulster hooker Paul Shields will captain an Irish Development XV against Argentina at Donnybrook next Wednesday.
Ireland: Murphy (Leicester); Horgan (Lansdowne), B O'Driscoll (Blackrock, capt), Maggs (Bath), Bishop (London Irish); Humphreys (Dungannon), G Easterby (Llanelli); Horan (Shannon), Sheahan (Cork Constitution), Hayes (Shannon), Cullen (Blackrock), O'Kelly (St Mary's), Quinlan (Shannon), Dawson (London Irish), Foley (Shannon). Replacements: Byrne (Blackrock College), Corrigan (Greystones), M O'Driscoll (Cork Consitution), Miller (Terenure), Stringer (Shannon), O'Gara (Cork Constitution), D'Arcy (Lansdowne).
