Deliberations over the All Blacks' midfield selections for the third test will focus as much on combinations as on individuals.

The All Blacks are preparing for the 3rd test in Hamilton, Aaron Cruden and Dan Coles are wanting to make it a clean sweep while Asst coach Ian Foster loses Conrad Smith to injury but welcomes back Kieran Read to the All Blacks.

In a straight skills comparison, Malakai Fekitoa comes out ahead of Ryan Crotty. Fekitoa has fast feet, acceleration, a supreme fend and explosive defence - all the skills required to play centre at the top level.

He is viewed as the most likely and certainly the most exciting heir to Conrad Smith.

But there are other questions for the selectors to ask this week when they come to pick their No 13.

All Blacks centre Conrad Smith will miss the third test against England and is in doubt for the remainder of the Super Rugby season after breaking a bone in his hand. Richie McCaw and Steve Hansen front the Hamilton media as they look to continue to 'make things tough for England.

Fekitoa has settled well into All Black life, and the coaching panel showed their faith in his temperament as much as his ability when they thrust him into action at Eden Park to make his test debut with the game locked at 9-all.

Assistant coach Ian Foster explained why they felt confident injecting Fekitoa at such a critical juncture in the opening test.

"We have been impressed with the way he has handled himself since he has come in," Foster said.

"We saw enough during the week from him to think that he could deal well with the pressure side of it. For us it became a decision we didn't think too hard about."

England coached Andy Farrel and Stuart Lancaster lament the critical decision making that let the All Blacks dominate the third quarter of Dunedin's second test match.

But starting a test is another mental challenge again and the selectors don't want to push Fekitoa too hard too soon.

They suspect England will return the destructive Manu Tuilagi to the midfield, and he gives even the most experienced test performers significant defensive challenges.

Crotty, with five tests behind him, is probably the safer pair of hands.

Perhaps, though, the biggest consideration is the balance of the midfield. Ma'a Nonu and Fekitoa are both direct, line-breaking, explosive runners.

Such combinations don't often work - as evidenced in the three times Nonu and Sonny Bill Williams played together for the All Blacks.

Diversity is often the key to a midfield partnership and it is questionable whether Nonu and Fekitoa will make a good fit. They will duplicate rather than complement each other - but that might prove too hard for the selectors to resist.

They may be willing to sacrifice some subtlety and distribution capabilities to instead present an immensely physical midfield - Nonu and Fekitoa running hard and straight all night might not confuse England, but it would drain them.

As to who will play for England in the midfield, Nonu's impression after the second test was that it wouldn't particularly matter as both the possible combinations were a handful.

"Pretty even," he said when asked which of Kyle Eastmond and Tuilagi or Billy Twelvetrees and Luther Burrell caused him and Conrad Smith more problems.

"It was pretty 50-50. We had our moments and they had theirs.

"It's hard to get a grasp on playing those midfielders because you don't see them week in week out the way we do with the likes of Australia and South Africa as we play each other a lot. I thought it was a fair contest."