But after making a fine second-half cameo against Haiti and scoring in Argentina's sole pre-World Cup friendly the striker will begin the tournament as first choice over Juventus' Gonzalo Higuain.
The Argentina team confirmed by the coach in Friday's press conference poses no surprises, based on the side Sampaoli has been training with throughout the week after seeing their final friendly against Israel fall through due to protests over the fixture.
Chelsea goalkeeper Willy Caballero therefore starts ahead of Franco Armani and Nahuel Guzman in goal, following the withdrawal of regular No. 1 Sergio Romero due to a knee problem shortly after the World Cup squad was confirmed.
According to Sampaoli, Caballero's position as deputy to Romero in the last friendly call-up in March helped him win out over his two rivals within the squad.
"Aside from the similar qualities of all three goalkeepers, who were all great, we have opted for Caballero because we have had more time to work with him," the coach told reporters.
"But all three are in great form."
Elsewhere City and United rivals Nicolas Otamendi and Marcos Rojo will team up in the middle of defence, while Javier Mascherano is set to overtake Javier Zanetti as Argentina's most-capped player as he starts in midfield for his 144th appearance for the Albiceleste alongside Lucas Biglia.
Captain Lionel Messi, meanwhile, will be joined by Independiente's Maxi Meza and Angel Di Maria of Paris Saint-Germain in a trio behind sole striker Aguero, although he will be expected to push further up and accompany Kun in attack when Argentina are in possession.
"Messi looks good, very excited. With the talent he has he should not be under much pressure, it helps him enjoy his game," Sampaoli said of his No. 10.
"I do not see this World Cup as Messi's last."
Confirmed Argentina XI: Caballero; Salvio, Otamendi, Rojo, Tagliafico; Biglia, Mascherano; Meza, Messi, Di María; Aguero.