This week's rest comes after Smith also sat out the Pumas test in New Plymouth earlier this year.
Smith is far from alone in being spelled. Kieran Read, Sam Whitelock, Sonny Bill Williams and Wyatt Crockett don't join the All Blacks in London until later this week, while other senior players did not travel to Argentina this year.
The All Blacks have not selected the same starting team in successive weeks since the World Cup final two years ago.
It hasn't always worked as planned but, on the whole, the benefits have been obvious.
The week after Smith was rested from the Pumas test, he returned in superb touch against the Springboks in Albany where his brilliant quick tap and kick set up Rieko Ioane for the opening try.
Smith is an energetic, competitive character at the best of times. As he explains, the extra spark after a week off is no coincidence.
"I feel like in the past we have tapered away on the end of year tour but we've come in refreshed and mentally excited about trying to finish the year on a high which is a challenge when you've played 20 odd games already this year," the 28-year-old said.
"I don't feel like I'm physically trying to hang on. We've been rested or not picked which is a blessing in disguise. When you get told early in the week you're pretty gutted but then you get back in the zone about team first.
"When you get rested it sucks but you know the next week you're going to be humming and you can attack that game. As you get a bit older that's gold and you can go for another month or whatever is needed."
This week Smith can concentrate on fine tuning tactics around the scrum law changes which give halfbacks control about when to put the ball in rather than referees deciding.
Tweaks to allow No 8s the freedom to pick up the ball from under the locks' feet should also benefit the All Blacks' quest to use the ball from this platform, and utilise Smith's bullet pass.
"It shouldn't change our game too much. I don't want to give away too many hints about why and when the nines are going to put the ball in.
"It sometimes feels like a bit of a hoodoo when the ball gets stuck at the locks' feet and you can't grab it and you get penalised so I'm glad they've cleaned that area up."