Gregor Paul: Can Nonu and SBW work?

Sonny Bill Williams at 110kg and Ma'a Nonu at 104kg pack a frightening punch. Photo / Getty Images.

If, as expected, Ma'a Nonu and Sonny Bill Williams pair up in the All Black midfield next week, don't assume it will be a partnership that delivers the sum of its component parts.

It's hard not to be excited by the potential of those two working together.

They are the two most powerful midfielders in world rugby - no one breaks the line better than those two, no one presents more of a physical handful. Williams at 110kg and Nonu at 104kg pack a frightening punch.

But...a word of warning: rarely do partnerships of this type work. The similarities between the two are both the strength and weakness of the combination.

Variation is critical to shift defences and find holes. The best partnerships have had contrasting individuals - men who between them offer a range of skills. Tim Horan and Jason Little, maybe the best of all time, had the directness of the former and the elegance of the latter: one could bash, the other could glide and having played regularly together since their early teens, they instinctively understood each other.

Walter Little and Frank Bunce were starkly different players yet formed a snug fit when they lined up in numbers 12 and 13.

Nonu and Conrad Smith have formed an enduring and brilliant partnership for the All Blacks since 2008. Those two work together - much like Horan and Little.

The danger for the All Blacks is that in fielding Williams and Nonu, they will be predictable. Still enormously difficult to actually stop and defend effectively against, but at least the Wallabies will know what is coming.

That's what happened when Nonu and Williams were paired together back in 2010. It was Williams' test debut and he played at centre, Nonu asked to guide him through the clash with England. They never gelled - their collective awesome power couldn't be harnessed because they ran similar lines, had the same instincts and tended to take each other's space.

Nearly two years on and Williams especially is a vastly improved player and more likely to be asked to play at second-five - a position to which he is more accustomed. Nonu is a mature and composed performer and able to slip out one berth with minimum disruption.

Most of this week and next - once Williams is actually cleared to play by his Japanese club - will be spent giving those two time together at training.

The coaches will know that they need to build some surprise into how they use their midfield - and yet, they won't want to try to be too clever and waste the obvious explosive power at their disposal.

It will be a tough balance to get right on game day: the Wallabies will be aware of the threat, ready to charge off the line and close those two down.

With some innovation, creativity, thought and invention - the All Blacks could make this partnership work - as in really work. But if they sit back and think it will take care of itself, that simply having two huge men out there will be enough in itself, August 18 will be a long and disappointing night.