The 28-year-old has scaled all the heights, come through all the high-pressure tests, and suddenly found a new place to jump to. The re-shaped Crusaders have responded brilliantly to his leadership. Whitelock has gone from outside the captaincy debate to the middle of it. The Crusaders' way is the All Blacks' way, of sticking to your job under pressure.
The other candidates are, apparently, flanker Sam Cane and fullback Ben Smith.
Number seven is not a great place to lead a team from. It's too all-action, too maverick. Richie McCaw did it by example, carried by an aura and reputation second to none. It took him a while to settle in though.
If the going gets tough, if the All Blacks fall behind, if the penalties are going against them, I don't fancy Cane as being the man to sort it out. The Chiefs looked rudderless against the surprising Sunwolves this weekend. They finished the game all at sea, trying to find a try against 13 opponents and stuffed it up.
Cane, to many of us, is not even an automatic test selection, although the selectors might look at it differently. Cane is also more likely to be dragged off in the second half of tests than Whitelock.
And if Cane does start, he might have enough on his plate, as the "veteran" in a potential new-look test loose forward combination minus Read and the injured Jerome Kaino.
No small matter, there have been very concerning off-field incidents involving the Chiefs which do not reflect well on their leaders. Cane's time may come, but it's not now, not against the Lions.
Ben Smith is the boy next door who keeps knocking on the referee's door. As the Highlanders captain, he's no shrinking violet when it comes to questioning and advising the match officials. This is not necessarily a good thing - referees can react badly.
Smith has the playing pedigree, the respect, but fullback isn't a great place to captain from, away from the central action, away from the ref. It's hard to think of any great test fullback captains in the modern era. He might switch to wing during games, the worst captaincy position.
In Smith's case, vice captaincy was not necessarily a stepping stone to the captaincy. It was more a way of spreading the leadership, between backs and forwards.
And finally, the great All Black captains have been great forwards. Whitelock is one. Case closed.
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What a terrific heavyweight title fight, the best for many, many years.
Anthony Joshua v Wladimir Klitschko at Wembley was momentous, a brutal, clean hitting contest which ebbed and flowed.
As for the multi-million dollar question: is Joseph Parker up to this class? Answer: Wouldn't have a clue, but if pushed, would guess maybe not.
The commentators were already talking about a re-match between the Ukrainian veteran and the new champ Joshua. Getting the fight at the right time will be difficult enough for Parker's crew.
If Parker can win this week's fight against an unknown Romanian in what is not much more than a South Auckland scout hall by world boxing standards, then Duco needs to get cracking on a date with the American WBC champion Deontay Wilder.
