Because of this lighter-than-expected workload this year, it is understood Smith hasn't entirely ruled out continuing beyond the two Bledisloe Cup tests, but the plan at this stage is to take his break from August 27 and return for the Highlanders next season.
That would give Smith at least four months off and see him miss four further Rugby Championship tests; the final Bledisloe in Brisbane and end of year tour, which is expected to feature five games; three tests.
"Contractually he's on sabbatical now," Alcock said.
"As soon as Super Rugby finished he was entitled to take it. He has decided to make himself available for the two Bledisloe games because he has missed some rugby this year.
"The expectation is he will start his sabbatical after those two games.
"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.
"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."
Alcock charted similar breaks for Richie McCaw and Dan Carter. McCaw opted to take time out to travel away from rugby for six months, while Carter spent one of his two breaks playing for French club Perpignan.
Alcock confirmed Smith would not follow in Carter's footsteps and chase a lucrative short-term stint overseas. Rather, he was looking forward to spending time at home with his wife, their two young children and family.
"It's always been a non-playing sabbatical with the intention of allowing his body a break. 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 be 33 by the time the 2019 World Cup rolls around in Japan and his sabbatical clause was a major factor in him knocking back an enticing offer from French club Pau, among others, to re-sign with New Zealand Rugby through to 2020 in February.
"It was one of a number of really critical points for him. The assessment was we needed to do as much as we could to get him in good shape to get to 2019 and the reality is he felt he needed this kind of break to give himself the best possible chance of playing that long.
"My experience with the guys I've had who have taken those longer sabbaticals is they comeback renewed and fresh. The sabbatical has a very real place in a rugby plan for certain individuals.
"Ben is at the point where he really needs to have some time away. He's also a family man and he likes his time at home and with extended family."
Smith's absence from the All Blacks later this year is expected to pave the way for Jordie Barrett to enjoy some extended time at fullback.
Hurricanes team-mate Nehe Milner-Skudder, Israel Dagg and Damian McKenzie are other options.
