Hooker isn't really the big worry for the All Blacks. Nor, now that Malakai Fekitoa has emerged so well, is it centre. Openside is covered by Sam Cane and there is choice, choice and more choice at first-five.
The only thing they don't have well covered is No8 and Kieran Read has become the only man the All Blacks simply can't afford to be without.
If he's not available, so much comes off the table. With Read at No8, anything is possible. They really need him to be fit to play England.
They need his range. They need his ability to hit into the midfield two passes after the ruck. They need him to win short kick-offs. And, most of all, they need him positioned second man from the touchline where he can offload or drive through tackles.
It's in that wider channel where the All Blacks have become so deadly. No other team in test football is able to play the game that far from the breakdown. Not effectively, anyway.
But all of last year, because of Read's speed, mobility, ball skills and vision, the All Blacks were able to create mismatches and exploit them. If there's no Read, a little doubt kicks in as to whether the All Blacks can be the same team. No Read, and England will take more than a little confidence from that.
Last year at Twickenham, Read gave a performance that probably secured his World Player of the Year award.
England crammed the 126kg Billy Vunipola into their No 8 shirt and got 60 good minutes out of the youngster.
It was 60 minutes of up-the-guts honesty - direct, bruising and damaging. There was much to admire in Vunipola's approach and he drove his side forward, ever willing to carry.
But the simplicity of his offering was made to look like a weakness rather than a strength by Read. His contribution lasted 80 minutes and he varied his running lines.
He threw one incredible pass around his back for Julian Savea to score. He charged over himself and made crunching tackles. He won lineout ball, stole turnovers and won kick-offs. He played narrowly. He played wide and the rhythm and tempo of the All Blacks - that ability to switch gears - was essentially what did England in.
And so much of that rhythm and tempo is set by Read, or at least made only possible because Read can be where the team need him to be.
So what if he can't shake the affects of his concussion or flu? What if he can't get the conditioning load and contact work under his belt to be a starter at Eden Park?
It's unlikely, but the question is still valid because what if he succumbs to some kind of ailment during the season? What then?
There are plenty in the wider training squad who can get by at No8. Richie McCaw has played there in tests, as has Liam Messam, and Jerome Kaino is operating there for the Blues. Short term, one of them can stand in for Read if needs be - probably Kaino who is closest in size, mobility and athleticism.
But the All Blacks need a longer-term, permanent back-up option at No8 to Read. All Blacks coach Steve Hansen has always felt Victor Vito would gravitate to the position as he got older. He probably will, as he ticks every box bar one - that elusive physical edge. Will he ever find it?
Luke Whitelock is improving but is he ever going to offer the same breadth of qualities as Read?
The answer may lie outside the current squad. Brad Shields, still only 23, has time yet to convert into a specialist No8. He has the frame - 1.94m and 110kg - legs, lungs and the nasties.
The other man of intrigue is Liam Squire at the Chiefs. He's even bigger, at 1.95m and 113kg, and yet has shown incredible pace when fit this year.