Ross Karl: Jerome Kaino and Matt Todd in two different states of All Blacks limbo

OPINION: The changing of the guard is one of the more intriguing times of a sporting team.

Jerome Kaino's absence earlier in the Rugby Championship - and now from Sunday's test against Argentina - has certainly accelerated the All Blacks' transition process at blindside flanker.

There is no doubting Kaino is one of the greats. He is a two-time World Cup-winning, 81-test enforcer, but pedigree counts for little when young talents can no longer be ignored.

Liam Squire is playing brilliantly, while Vaea Fifita's shown great promise and has been preferred to Kaino at six.

Steve Hansen says, if the 34-year-old wants his jersey back, he'll have to earn it. You'd have to assume that's unlikely to come next week against South Africa, when Squire is expected to slot back in. 

If he's to earn his jersey back this year, that may have to happen on the training paddock.

Kaino started his All Blacks career in 2004 against the Barbarians and unless there are injuries, November's game against them may be his next chance to wear black.

Unless he's given a shot in the dead-rubber Bledisloe encounter in Brisbane.

Of course, even if he's not on the field, he'll be a key member of the side.

Kaino is a rugby head. His knowledge of the game is very good and from my experience, when tapped into, he can be one of the most informative interviews out there.

His experience will be paramount in making sure the baton is passed most effectively.

While it will be interesting to see if Kaino makes it to the 2019 World Cup, another person in that same category is Matt Todd.

Once again, the All Blacks have favoured him as starting openside, preferring to bring Ardie Savea off the bench.

While others will debate the point, there is little doubt in my mind that Sam Cane is a 'must-pick' All Black. Todd has joined a long list of very good Kiwi players stuck behind guys that just can't be left out.

Think Frano Botica or Marty Holah.

Todd has performed beautifully in his eight tests, he's taken four years to gather them. He doesn't have the same impact as Savea, so can't take his role in the squad.

Steve Hansen says Todd is one of his favourite players, so it's an unfortunate circumstance for Todd that the team doesn't carry three opensides. 

Hansen would love to keep Todd, but says players have to make their own calls and that means he can't keep everyone around.

That's probably why the 29-year-old has only agreed to a one-year deal with New Zealand Rugby. It must be hard to plan your future, when your favourite carrot is dangled in front of you, but you only get a taste of it every now and then.

When it comes to Matt Todd, the All Blacks selectors must somehow figure out how to have their cake and eat it too, so he doesn't leave before the next World Cup.

So they dangle that carrot and he is the cake. Call him New Zealand Rugby's carrot cake.

Newshub.