If they are left uncertain about Thomson's ability in that role, they could bring in another specialist to back-up McCaw which would leave Messam and Vito out of the World Cup.
"The situation is that we have Thomson who is 29 and has played a lot of footy," says Henry.
"He's hardened, having played 20 tests, and we have got Daniel Braid who is the only other experienced seven but he hasn't played a lot of footy this season.
"Then you have Matt Todd and Luke Braid who are both kids. They are good players but do you take a hardened old bugger who has done it?
"These are the two schools of thought and there is an opportunity to see Adam do that job," says Henry.
Both Todd and Braid are uncapped and the latter would be following in the footsteps of his older brother Daniel should he be the surprise selection on Tuesday.
Daniel Braid was the bolter in the 2003 World Cup squad and would have been a contender this year had it not been for a neck injury.