The Albiceleste boss has a final chance to consider his best team, with several players set to be given the opportunity to impress ahead of the World Cup
The fixture in Bucharest will be the first friendly of the year for the two-time World Cup winners and the final game before Sabella announces his squad for the showpiece event in Brazil.
While some decisions are all but certain - the inclusion of Barcelona star Lionel Messi and the likely absence of national side outcast Carlos Tevez among them - Sabella still has choices to make.
Catania defender Gino Peruzzi and Getafe's Benfica loanee Lisandro Lopez both forced their way into the reckoning and could feature on Wednesday, while Tottenham misfit Erik Lamela is a doubt for Brazil with a back injury.
Despite the potential absence of Lamela and Tevez, Argentina have the likes of Messi, Sergio Aguero and Gonzalo Higuain to call on in what will likely prove a fearsome forward line.
Sabella stated to the Corriere dello Sport recently: "Tevez? I will not comment on it.
"I'm surprised with the season of Higuain at Napoli. He's a great player and has done things very well."
Wednesday's encounter will be the first between the sides since the five-goal thriller at the World Cup in 1994, when Romania came out on top in America thanks to goals from Ilie Dumitrescu and Gheorghe Hagi.
While Romania are some way off the quality of the side led by Anghel Iordanescu two decades ago, they remain a difficult proposition, especially on home turf.
Victor Piturca's team have lost just once at home in their last eight games - a 2-0 defeat to Turkey in September - and came close to joining Argentina at this year's World Cup.
Having finished second in Group D of qualifying, Romania fell to Greece over two legs in the play-offs and have yet to return to action since their dreams of reaching Brazil were ended.
After taking on the world's third best team, Romania travel to Algeria before seeking revenge in their Euro 2016 qualifying opener against Greece in September.