Versatile Argentina back Juan Cruz Mallia has been ruled out of the remainder of the Nations Championship with a knee sprain, the Argentine Rugby Federation (UAR) announced on Monday.
The 30-year-old left the field just after the hour mark in Friday's loss to Ireland in Dublin and has been replaced in Felipe Contepomi's squad by the uncapped 27-year-old Tobias Wade.
Toulouse's Mallia, who can play across the back-line, only returned from a serious injury to the same knee in September after having been sidelined for almost a year.
Contepomi has also added hookers Bautista Bernasconi and Facundo Bosch to his side after the experienced Julian Montoya suffered a head injury in the Irish capital.
No 8 Facundo Isa has returned to the set-up, having been released to play for club Pau last weekend.
The Pumas play Italy in Genoa on Saturday then head to France a week later before a standings match held at Twickenham on the weekend of November 27-29.