New Zealand will be without lock Sam Whitelock and loose forward Liam Messam for the crunch clash against South Africa on Saturday.
Whitelock suffered a rib injury in the 28th minute after falling awkwardly at a line-out and was replaced by Jeremy Thrush, while Messam hurt his quad scoring New Zealand's second try in their 28-9 win against Argentina in Napier and was replaced by Sam Cane shortly after half-time.
"[Whitelock] has got a rib cartilage rather than a rib fracture so we'll have to see over the next couple of days how quickly that comes right," All Blacks coach Steve Hansen said.
"But worst case scenario is probably four weeks and best case scenario is probably three."
Messam is also expected to be out for three to four weeks.
Whitelock's absence means Thrush, who impressed against the Pumas, is likely to be retained alongside Brodie Retallick at Westpac Stadium.
Thrush was not part of the initial Rugby Championship squad but was called in when Patrick Tuipulotu (ankle) and Dominic Bird (toe) were ruled out.
Hansen said both of them were well on the road to recovery with Tuipulotu the more likely of the two to be available in Wellington.
"Patrick has a good chance of being available but obviously hasn't played for some time," Hansen said.
"Dominic is probably a week away. We won't panic about that. We'll get down to Wellington and see how everyone is.
"Patrick and Dominic are getting closer and closer to playing so we'll make some decision about how they are early in the week and go from there."