Wallabies coach Robbie Deans faces the dilemma of choosing either Mike Harris or Pat McCabe out of position and in the firing line at fullback against a Pumas outfit desperate for an Argentine ambush.
Harris looms as the more likely pick out of the pair of regular inside centres who are left as the leading options to become Australia's fourth custodian in five Rugby Championship matches.
No.15 has been a problem position for Deans with Kurtley Beale twice dropped from fullback and then Berrick Barnes and Adam Ashley-Cooper suffering sickening injuries in the weekend's 31-8 loss to a rampant South Africa.
Back-up Luke Morahan has just flown into Rosario but the selectors have all but ruled the Queensland speedster out of a start due to his late arrival and lack of preparation for the role.
Beale is the only other player left in the injury-ravaged squad with Test starting experience at No.15, but Deans indicated he can't afford to take his attacking spark away from five-eighth where he starred despite a shaky, pressured platform in Pretoria.
"A tough circumstance for (Beale) not only going back to five-eighth but also when you look at the nature of the game," Deans said. "He didn't get a great platform but he did offer a lot to the group.
"He got us on the front foot through his efforts ... he was great."
The besieged coach, whose future is set down for review after the third Bledisloe match on October 20 in Brisbane, listed fellow former Kiwi Harris, the hard-running McCabe and rookie winger Dom Shipperley as the contenders.
Harris scored a second-half try in Pretoria when playing fullback but his only other recent experience was for Queensland last year in Johannesburg where he struggled under the high ball.
There is sure to be plenty of garryowens raining down at Estadio Gigante de Arroyito on Saturday night with Pumas flyhalf Juan Martin Hernandez among the best kickers in the game.
Incumbent No.12 McCabe played most of the 2011 Super Rugby season at fullback for the Brumbies before being converted to inside centre but less change is becoming better for a Wallabies side racked by injuries.
They have received some welcome good news on the injury front with winger Digby Ioane (knee), hooker Tatafu Polota-Nau (head, shoulder) and No.8 Radike Samo (shoulder) all set to overcome painful knocks.
Deans said the trio - arguably the Wallabies' most destructive ball-runners - were recovering well and should be available for selection on Thursday.
Centre Anthony Faingaa has also been cleared of concussion and can replace Ashley-Cooper in the midfield while there's hope lock Sitaleki Timani (hamstring) can finally return.
The Pumas, searching for their maiden win in the rebranded tournament, have far less disruptions but will be forced to make one change to their squad with utility back Martin Rodriguez to undergo shoulder surgery.