The back-to-back world champions are gearing up for a demanding year, featuring the inaugural Nations Championship, the much-anticipated four-Test Greatest Rivalry series against New Zealand, and a non-cap match against the Barbarians in Gqeberha on 20 June.
Their Nations Championship campaign kicks off against England at Ellis Park on 4 July, followed by home matches against Scotland at Loftus in Pretoria and Wales at Kings Park in Durban.
"The focus is very much on that Barbarians match and building into the England Test at Ellis Park," Erasmus said during a press conference in Cape Town on Monday.
While winning remains paramount, Erasmus stressed the importance of long-term planning and succession.
"We averaged nine changes per game last year, so we're not under pressure to suddenly experiment," he said. "But depth is crucial. You might lose four or five players in one position. Succession planning is key. If we keep winning, continuity helps. But we'll always try to build five or six deep in every position. That's what gives you a chance at a World Cup."
Erasmus, who called up 49 players for a Springbok alignment camp in Cape Town this week, added: "I think we're OK. We've always said that about 18 months out from a World Cup you know who will probably make it and who won't. We definitely know much more now than we did 48 or 36 months ago."
On how many players he might use during the coming season, Erasmus added: "Maybe we'll use 51 again, maybe 57, maybe 33. It depends how the year unfolds. But at Test level, we will always go out to try and win. We even tell the team that if things go our way this weekend, this is probably the team that will play next weekend – with a caveat that if we lose momentum, we can change."
Erasmus highlighted the importance of having multiple options in every position, citing the example of Stephen Donald, who was drafted in by the All Blacks as emergency cover during the 2011 World Cup after their three first-choice flyhalves were ruled out, and kicked the winning penalty against France in the final.
"The big thing we're trying very hard to do behind the scenes, with SA Rugby and the franchises' help, is to make sure that in every position we can afford to have five or six players go down."
"We are not saying all of those guys will have played come the end of the year, but in terms of succession planning, hopefully the guys are in place," he added.