Ramiro Herrera, who until now has 37 games in his blue and white shirt, will no longer be available to the national team.
The reason? The forward will move to France next month to join the Stade Français and, as a result, will no longer be eligible.
The 28-year-old pillar had previously played for Castres before returning to Argentina to play for Jaguares in Super Rugby.
He joins fellow Pumas Juan Imhoff and Facundo Isa in the division.