But it is Aaron's absence, rather than Ben's, which presents Highlanders coach Jamie Joseph with the bigger challenge.
With Japanese halfback Fumiaki Tanaka also unavailable, Joseph has called in Bay of Plenty's Te Aihe Toma and Manawatu's Jamie Booth to fill the vacancy behind the pack for the warm-up game against the Crusaders in Oamaru this afternoon. The match will be broadcast live on Sky Sport 1.
"They are very young and inexperienced but in the ITM Cup they are two halfbacks that we tracked when we were contracting our players,'' Joseph said.
"Obviously, we've got Aaron and the desire to sit behind the All Black halfback isn't high for some of the players who aspire to play week-in week-out.''
With Otago's Josh Renton sidelined with injury, and Southland's Liam Howley also out, halfbacks are in short supply.
"You've got five franchises - that's 15 halfbacks - and so when a couple get injured .... you are really looking at the next best players. And we just think these two guys are pretty exciting and play the way we want them to play.''
Waikato hooker Hame Faiva remains in the squad for the injured Liam Coltman, while Otago midfielders Michael Collins and Fa'asiu Fuatai provide cover in the midfield.
Marty Banks will start at first five-eighth but Otago and University A pivot Fletcher Smith will get an opportunity in the second half.
Both teams have named 30 players and Joseph said the Highlanders would switch the team at halftime so everyone should get a run.
"This is a game we sorely need because we have not played for three weeks.
"One of the big reasons we won the championship last year was everybody that got an opportunity to play really contributed and we're really reliant on that this year.''
The Highlanders have nine players unavailable due to international commitments and will have to make do without the Smiths, and All Black centre Malakai Fekitoa, for their match against the Kings in Port Elizabeth next Sunday as well.
The All Blacks who get the week off will join the Highlanders in Argentina for their match against the Jaguares the following weekend.
