"He's had a busy season as well, so just how we treat him, we'll have to see. We might look at doing similar stuff with Tarms and Ma'a and try to get them ready for the Investec [Rugby Championship] series."
Nonu said he was always keen to wear an All Blacks jersey but conceded Williams was the form player.
"There's someone else playing out of his skin and is probably in front," he said. "When it comes to this team you help each other, really. I believe in people being rewarded."
The 30-year-old, who has played 66 tests, has had precious little reward at the Blues this season. While he showed some good touches in the loss to the Chiefs at the weekend, it was his impact as a substitute in the second half against the Highlanders a week earlier which caught the eye.
He was on the field only minutes but easily took the mantle as the best player wearing blue. Nonu said being back in the All Blacks environment earlier that week had helped lift and invigorate him.
"When I left the All Black camp I wanted to be part of this team. It brings the best out of you. When you go through this camp you keep learning. I can't really say I'm tired. It's professional sport, I've just got to roll with it."
It is likely that Williams and Conrad Smith will be the midfield partnership for the first test, with Piri Weepu starting at halfback inside Dan Carter. The only real question mark hangs over the wings.
Specialist left wing Julian Savea could mark his call-up by playing there on debut, with the selectors having Zac Guildford and Hosea Gear, also left wings, to choose from on the right.
However, if Israel Dagg, the incumbent, is chosen at fullback, the selectors could look at Ben Smith as an option on the right.
A conservative approach for the forwards would see a front row consisting of Tony Woodcock, Andrew Hore and Owen Franks, with Ali Williams getting the nod at lock alongside Sam Whitelock. The loose forwards would be Richie McCaw, Kieran Read and Adam Thomson.
Hooker Keven Mealamu, tied on 92 caps with the record-setting Sean Fitzpatrick, is likely to be unavailable until the second test in Christchurch at best due to his calf injury. Hika Elliot will get the nod as cover for him on the bench.