Hooker, halfback and the midfield are the areas where the All Blacks may need new blood for the 2015 World Cup campaign - with lock, openside flanker and wing also having gaps that may need filling. Trying to select prospects for a global tournament four years hence is a bit like trying to predict earthquakes - an exact science, it's not. There are too many variables.
The game and its rules could change - let's hope so - and the strategic selections which marked Graham Henry's 2011 squad (such as wingers selected specifically to handle the high ball) may also change. But there are clear and key areas in the All Blacks which should be open for contest come the next World Cup. Like hooker.
All three incumbents may have problems getting to the next World Cup. He seems indestructible but it's likely that Keven Mealamu won't make it through to England, the venue of the next World Cup. He'll be 36 - although it's worth pointing out that Brad Thorn was that age in this year's tournament and nothing should be taken for granted where the durable Mealamu is concerned.
Andrew Hore will be a year older (37) by then and seems most likely to be back farming in the Maniatoto. And you would not place a lot of money on Corey Flynn (34 in 2015) being there either, even if he makes it that far without breaking any more bones.
As for halfbacks, Piri Weepu will be 32 in 2015 - not too old by any means but most of us would put money on him deciding to get out at the top. Jimmy Cowan will be 33 by then and fell out of favour in RWC 2011 and Andy Ellis will be 31 - again, not too old but the competition will likely be fierce.
As for the midfield, Ma'a Nonu will be 33 and Conrad Smith 34, while Richard Kahui and Sonny Bill Williams will only be 30 - but anyone who thinks the former will be injury-free and the latter still in rugby union may not have been studying the form over the past two years. So who will be the likely challengers?
The front row is probably the most difficult area to predict as players such as Owen Franks - world-class at 23 - are rare and many hookers and props don't show their best until later in life; current contender Hika Elliott will be 29 by then.
But the following players may be worth watching in coming rugby seasons:
Dane Coles (Wellington) Burst on to the scene with some effervescent performances and earned a big tick from as savvy a judge as Sean Fitzpatrick. A mobile, running hooker, Coles (now 24, 1.84m, 103kg) has had some disciplinary problems and lost form and profile after being stuck behind Hore at the Hurricanes - but with the All Black now at the Highlanders after the well-publicised difficulties of last season, it could be time for Coles to shine.
Shae Tamati (Hawke's Bay) Highly mobile and a skilled ball player, Tamati is small for a modern hooker (22, 1.75m, 96kg) but then so was Mealamu when he started out. He has excellent ball skills and speed and is well suited to the running game. He was a New Zealand under-20 world champion in 2009-10.
Codie Taylor (Canterbury) A member of the successful under-20 world champion team last year, Taylor (20, 1.83m, 109kg) hasn't managed to force his way into this year's Crusaders Super 15 squad against another candidate - Quentin MacDonald (Tasman, 22, 1.81m, 103kg), another dynamic runner with a high work rate; and Flynn - but Taylor is regarded as one for the future.
Few surprises here, as all will be playing Super Rugby this year:
Alby Mathewson (Auckland) Provided he gets a run at halfback with Piri Weepu at 10, could force his way into All Black selection with his sniping, speedy running. Will be only 29 by 2015.
Tawera Kerr-Barlow (Waikato) Has already looked good in his short time with Waikato and the Chiefs and could figure in the next All Black campaign. Only 21, he has a way to develop yet but is a strong, bustling halfback with a try-scoring habit.
TJ Perenara (Wellington) Still only 19, this firecracker halfback has been marked as a future All Black since last year when he was plucked out of Mana College's Year 13 to play against Southland in the ITM Cup. A Junior World Cup winner with the under-20s and a creative player of pace and skill, he will get more game time with Weepu now at the Blues.
Perhaps the most competitive area when one looks at the firm hold Nonu and Smith have had on the All Black midfield for years.
Robbie Fruean (Canterbury) Still only 23, was told by Graham Henry he had to increase his work rate to get into the All Blacks. If he does that, watch out - he is 1.9m and 105kg of brute and can punch large holes in defences.
Charlie Ngatai (Wellington) Another big man, this Wellington starlet had a reverse last year with injuries to a broken ankle and eye socket and missed much of the year. Only 21, he has time on his side but has already been paired with Fruean (when the latter played for Wellington) in a massive midfield.
Tom Taylor (Canterbury) Son of 1987 World Cup winner Warwick, he displays a similar cool head, awareness of space and distribution skills, plus the knack of making correct decisions. In the Crusaders' squad this season but will battle for game time with Fruean and Ryan Crotty. Can play 10 and is a reliable goalkicker, notching 20 points on his ITM Cup debut.
Ryan Crotty (Canterbury) Seems to have been around a long time already but is only 23. A solid, aggressive midfielder, he is 1.81m and 100kg and a bit of a handful on defence and attack. If another player of this type is desired, the Highlanders' Shaun Treeby (22) could also be a prospect.
While those are the main areas where replacements are almost certainly required, there may be others. Top of the list will be Dan Carter and Richie McCaw - though most of us will figure that Carter (who will be only 32 in 2015) will be up for a third crack at the World Cup given his injury this year and the horrors of 2007.
However, McCaw may be another matter. Attrition through injuries could add to the fact that he will be 34 come the next World Cup. If he doesn't make it, cue a fascinating battle between Matt Todd (Canterbury, 23), Luke Braid (Auckland, 23) and Sam Cane - still 19, but 1.86m and 103kg and getting the same sort of rave reviews as a No 7 that a young McCaw did. He is apparently blessed with a perpetual motion engine like that of McCaw and Kieran Read.
Lock is another interesting area - Ali Williams will be 34 by 2015 and even Anthony Boric will be 30. Both will have work to do to seal an All Black place through to the next global tournament.
With Jarrad Hoeata first off the blocks to take the place left by Brad Thorn, young contenders such as Chiefs and New Zealand under-20s lock Brodie Retallick (20, 2.04m and 115kg) also seem likely to make a bid. Singled out by coach Dave Rennie along with Cane as one of the stars of the under-20s' World Cup win, Retallick has a high work rate and is mobile for a big man.
Another big bloke with a reputation enhanced last season is Taranaki and Hurricanes lock James Broadhurst (23, 2.03m and 117kg). Auckland's Liaki Moli (21, 1.94m, 113kg) is another former under-20 star regarded as a highly mobile, Thorn-type player with a big future. Wing Cory Jane will be 32 by 2015 and Kahui 30, though Isaia Toeava, Lelia Masaga and Rene Ranger will only be 29.
But some new blood may be needed - possibly from the likes of Sean Maitland (Canterbury, 23) Julian Savea (a horrible season last year but he has no Hosea Gear in front of him this time, has undoubted ability and is still only 21) and, for a real roughie, Canterbury's Patrick Osborne - who is 24 now but an interesting 1.86m, 105kg newcomer with a Fiji sevens background. Has to satisfy eligibility requirements but also has blistering pace, as does the Chiefs' Maritino Nemani.
If Aaron Cruden doesn't cement his place as Carter's back-up, the likes of Beauden Barrett (Taranaki and Hurricanes), Gareth Anscombe (Auckland), and Lima Sopoaga (Wellington and Highlanders) will be chasing him up. Other players already with big reputations who could force their way into selection matters include No 8 Luke Whitelock (now in the Crusaders squad and spoken of as the best of the Whitelock clan); North Harbour and Chiefs prop Ben Afeaki, Waikato and Chiefs prop Toby Smith (both only 23) and elusive Canterbury and Crusaders fullback Tom Marshall.By Paul Lewis Email Paul