“It’s a real honour to be able to represent my country in the World Cup and the fact that I can play with a great friend George will make it even more enjoyable,” Grace said.
“With the format being the way it is, it gives us the chance to gain some experience for the Olympics in 2016, which hopefully we can both qualify for too.”
Coetzee comes into the team for Richard Sterne, who was not available.
South Africa’s other top-ranked players Charl Schwartzel, Ernie Els and Louis Oosthuizen also ruled themselves out for selection.
Grace and Coetzee would be forced to miss the South African Open Championship being played at Glendower Golf Club in the same week.
Grace, 25, and Coetzee, 27, would attempt to become the sixth South African team to win the World Cup, following in the footsteps of Gary Player and Harold Henning in 1965, Bobby Cole and Dale Hayes in 1974, Ernie Els and Wayne Westner on home soil at Erinvale in 1996, Els and Retief Goosen in 2001 and Trevor Immelman and Rory Sabbatini in 2003.
The defending champions were the US, who won the title in China in 2011 at the Mission Hills Resort on Hainan Island with Matt Kuchar and Gary Woodland representing them. Kuchar returns to the event in 2013, this time with Kevin Streelman.