Sharks have also recruited French full-back Julien Laharrague, who has agreed a one-year deal after initially arriving from Perpignan earlier this season, together with Auch prop Benoit Bourrust.
Sale rugby director Philippe Saint-Andre said: "Julien has won 15 caps for France and there is a good chance he will be able to play for us during the World Cup.
"Munster came in with a very big offer for Julien, but I am pleased he has signed for Sale Sharks.
"Rudi is a tough attacking centre who has experience playing in Super 14s with Natal Sharks.
"And Benoit is one to watch for the future. Agen and Stade Francais both wanted to sign him but thankfully he chose Sale Sharks."