The 31-year-old All Blacks vice captain, widely regarded as one of the best fullbacks in the world, negotiated a sabbatical into his new contract in February and will be unavailable for eight internationals.
The break is aimed at ensuring Smith reaches the 2019 World Cup in good shape and follows a precedent set by Richie McCaw and Dan Carter, who both had sabbaticals between the 2011 and 2015 World Cups.
"Contractually he's on sabbatical now," his agent Warren Alcock told the New Zealand Herald.
"He has decided to make himself available for the two Bledisloe games because he has missed some rugby this year.
"We built in quite a significant sabbatical for him because to get him through to 2019 we felt that's what he was going to need physically and mentally."
Smith missed the last two tests against the British and Irish Lions because of what were initially thought to be concussion symptoms but later discovered to be caused by an inner-ear problem.
"What has changed is he was injured and had a reasonable break out of Super Rugby and missed a couple of Lions games so he's reassessed things and decided he was keen to be available for the next two games and then he'll take his sabbatical," added Alcock.
Smith had no intention of following flyhalf Carter by using his sabbatical to take up a lucrative contract in Europe, he said.
"It's always been a non-playing sabbatical with the intention of allowing his body a break," added Alcock.
"He's a player that pretty much plays every minute of Super Rugby with the Highlanders and with the All Blacks he plays high minutes as well."Smith will miss four Rugby Championship tests against South Africa and Argentina, the third Bledisloe Cup clash with the Wallabies in Brisbane on Oct. 21 and tests against France, Scotland and Wales on the end of year tour.
(Reporting by Nick Mulvenney; Editing by Peter Rutherford)
