Argentina could face a devastating blow with news that tighthead prop Ramiro Herrera faces surgery on his knee.
The 26-year-old requires an operation on his medial ligament and meniscus in his left knee, after going down in training this week.
As a result he will be absent for the upcoming pair of games against South Africa, and could miss the World Cup altogether.
His loss would have serious consequences for the Pumas, who are already without Juan Figallo after he picked up a serious knee injury last month.
Nahuel Tetaz Chaparro and youngster Matías Díaz are the remaining tighthead options in the squad.