A spate of injuries in the back-row has led to Dai Young being left short of options in recent weeks and the problem will only be further accentuated by Nathan Hughes' absence with England.
Carr, who has five caps for the Springboks, has spent his entire career in his hometown of Cape Town, featuring for the Stormers in Super Rugby and Western Province in the Currie Cup.
Having missed out on a place in the Boks' squad for the upcoming autumn internationals, the 26-year-old will spend the southern hemisphere's off-season in Coventry.
The flanker or number eight will arrive later this week, much to the delight of Young.
"Nizaam has a strong reputation for his defense, athleticism and linking play," Young told the club's official website. "We are pleased to be able to bring a player with international experience like Nizaam into the squad to bolster our back row options.
"I'm sure he will prove himself a valuable addition to the squad."