He hurt his knee in last Saturday's home win over the Springboks, the Argentine Rugby Union said on Monday.
Kremer hobbled off midway through the second half of Argentina's 29-28 home victory over the World Cup winners in Santiago del Estero on Saturday, and was left out of the 28-man squad for South Africa, where the two countries meet again in Nelspruit on Saturday.
The experienced Kremer's absence will be a blow to the Pumas' hopes of another upset win as they need a bonus-point victory at the Mbombela Stadium to snatch the Rugby Championship away from top-of-the-table South Africa.
The Springboks have a five-point lead over Argentina in the standings going into the final round of this year's southern hemisphere championship.
Kremer, who has 72 caps, is the only omission among the forwards from the squad for last week's Test, but among the backs Ignacio Mendy, Matias Orlando and Justo Piccardo have been cut for the trip as the size of the squad is reduced to 28.
ARGENTINA SQUAD:
Backs: Tomas Albornoz, Lautaro Bazan Velez, Gonzalo Bertranou, Mateo Carreras, Santiago Carreras, Santiago Chocobares, Lucio Cinti, Bautista Delguy, Gonzalo Garcia, Rodrigo Isgro, Juan Cruz Mallia, Matias Moroni
Forwards: Bautista Bernasconi, Ignacio Calles, Pedro Delgado, Thomas Gallo, Juan Martin Gonzalez, Santiago Grondona, Tomas Lavanini, Pablo Matera, Franco Molina, Julian Montoya, Joaquin Oviedo, Guido Petti, Pedro Rubiolo, Ignacio Ruiz, Joel Sclavi, Lucio Sordoni
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