By that logic, you wouldn't play any tournament as there is allways a risk of injury.
What he means is that some tournaments offer a prize money and ranking points that make it worth it to assume the risk of getting injured. Davis Cup (in the case of the RSA federation) doesn't.
Being the best South African player I'm sure you are in good position to negotiate that you will only play 2 matches max. If you want to play another tournament, that's up to you, I don't have a problem with it, but don't come up with poor excuses.
Two best-of-five set matches, in 2-3 days, that's not light on the body.
OMG, 3 times a year?!
How dare they subject you to such a sacrifice, specially for a guy who allways goes deep in the tournaments the week before, right, right?
Anderson doesn't usually go deep in tournaments but he tries to compensate that by playing week after week.
Anyway, the fact that he's currently the only top South African player, and they count on him so much to get Davis Cup victories, only aggravates the issue. If there were 2-3 players in the top 100 then it wouldn't be much of a big deal for the RSA federation to offer few money to the players, as they could alternate throughout the year.