Brumbies prop Guy Shepherdson admits his team-mates are struggling to understand rugby's new rules as they prepare for Super 14's toughest assignment, against the Crusaders in Christchurch.

The Brumbies copped an ELV lesson in last Friday's trial against the Hurricanes and Wallaby front-rower Shepherdson said the lopsided scoreline was partly due to the number of free kicks given away by the Australian side.

Most infringements at the breakdown now incur only the short-arm penalty, and the quick tap option that comes with it has been credited with speeding the game up enormously.

Coach Laurie Fisher said after the trial that referees' interpretations of the experimental rules had varied between Australia and New Zealand.

Asked if it all added up to confusion, Shepherdson told AAP: "A little bit.

"It's difficult to fully assess that at the moment.

"I think a number of us are still trying to adjust to it.

"I think part of it is, now that a lot of the rules have just come down to free kicks, there's a lot less warnings and a lot less verbal instruction while referees are just a lot quicker to give you a free kick rather than talk you through the awarding of penalties.

"I think everyone's trying to respond and react to these new rules and ... for the first few rounds it will be a bit of a mixed bag as far as everyone goes."

One thing for certain, though, is that big men like Shepherdson will be doing a lot more running than they have been used to.

"I think probably the biggest side of it is just the pace of the game," Shepherdson said.

"It just seems to be you're constantly running around. You're buggered and you're getting pretty tired. I don't know if it's confusion or just fatigue."

The Brumbies have been in New Zealand since last week's trial in Levin, near Wellington, training in Nelson as they prepare for the season opening clash with Robbie Deans' tournament favourites at the renamed AMI Stadium in Christchurch.

Minus departed superstars George Gregan, Stephen Larkham and Jeremy Paul, the Canberrans will head into the match as $5.50 outsiders.

"We certainly understand that we're underdogs ... but we have prepared well and we're quietly confident but not overly confident and I think that's quite a good thing," Shepherdson said.

"If we're able to get a win against the Crusaders it would set up our season beautifully and it would be a magnificent achievement."

Fisher on Wednesday named four new faces for the match, with flyhalf Christian Lealiifano and reserve back Tyrone Smith to make their Super 14 debuts and former Waratahs scrumhalf Josh Holmes and Stormers hooker Huia Edmonds to make their first appearances for the Brumbies.

Deans named three newcomers in his starting line-up - Kahn Fotuali'i at halfback, former Blues lock Ali Williams and young winger Kade Poki - while former Brisbane Bronco Brad Thorn will mark his return to Super rugby for the first time since 2004.

Brumbies: Julian Huxley, Mark Gerrard, Adam Ashley-Cooper, Gene Fairbanks, Peter Playford, Christian Lealiifano, Joshua Holmes, Stephen Hoiles, George Smith (capt), Jone Tawake, Adam Wallace-Harrison, Alister Campbell, Guy Sheperdson, Huia Edmonds, Nic Henderson. Res: Saia Faingaa, Salesi Ma'afu, Peter Kimlin, Julian Salvi, Patrick Phibbs, Tyrone Smith, Francis Faimifo.

Crusaders: Leon MacDonald, Kade Poki, Casey Laulala, Stephen Brett, Scott Hamilton, Daniel Carter, Kahn Fotuali'i, Mose Tuiali'i, Richie McCaw (capt), Kieran Read, Ali Williams, Brad Thorn, Greg Somerville, Corey Flynn, Ben Franks. Res: Ti'i Paulo, Wyatt Crockett, Michael Paterson, Nasi Manu, Andrew Ellis, Tim Bateman, Sean Maitland.

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