All Blacks coach Steve Hansen will have to reassess his options at openside flanker after Matt Todd was ruled out for four weeks with a broken hand.
With Sam Cane failing a head injury assessment during Saturday's Rugby Championship win over Australia, and Ardie Savea the only other specialist number seven, Todd had been expected to be drafted into the squad as cover for the September 9th game against Argentina.
However, the 29-year-old, who has eight test caps, five of which came last year, broke his hand in Canterbury's national provincial championship clash with Otago in Christchurch on Sunday.
"Matt Todd had a scan following Sunday's match against Otago, which has confirmed a fractured left hand," the Canterbury Rugby Union said.
"He has been seen by a hand specialist who, along with team medical staff, will continue to monitor his recovery.
"Matt will be in a splint for four weeks at which stage he will be reviewed by the specialist before being cleared to play."
After hosting the Pumas, the All Blacks face South Africa in Auckland on September 16th.
They then travel to face Argentina on September 30th and finish their Rugby Championship campaign in Cape Town against the Springboks on October 7th.