The pacesetting Waikato Chiefs have taken the opportunity to experiment as they escape another round of frenzied local derbies for their first trans-Tasman game of the Super Rugby season.
After a tough first three weeks against the Otago Highlanders, Auckland Blues and Wellington Hurricanes, the Chiefs have a favourable round-four match against the winless Rebels in Melbourne.
While their pressure eases, the unbeaten Western Stormers have a bye and the injury-hit Canterbury Crusaders host the Auckland Blues.
The defending champion Wellington Hurricanes, a week after they were removed from the top of the table by the Chiefs, will again be under pressure against the Highlanders with both sides also nursing several injured players.
"These derby matches are pretty extreme," Crusaders coach Scott Robertson said.
"It is Test match-level stuff, you can see the injury rates that come out of them and the attrition. The boys come off shattered."
The Crusaders are without All Blacks Israel Dagg, Seta Tamanivalu and Matt Todd as well as ex-Wallaby Digby Ioane with Robertson forced to make seven changes to his starting line-up for the Blues.
Tamanivalu will be replaced by his nephew Manasa Mataele making his Super Rugby debut, and on the plus side for the Crusaders, Owen Franks returns at tighthead prop and fellow All Black bookend Wyatt Crockett is on the bench.
The underperforming Blues, meanwhile, head to Christchurch with stinging criticism from coach Tana Umaga who said they "cannot be competitive in this competition with the error rate that we committed" last week against the Highlanders.
- Vickerman tribute -
The 2015 champion Highlanders gain one returning player, but have lost two more with Ben Smith cleared to resume playing while fellow All Blacks Waisake Naholo and Lima Sopoaga join six other regulars on the injury list.
Test apprentice Jordie Barrett fills the Hurricanes fullback role for Nehe Milner-Skudder who has a broken foot while regular flanker Ardie Savea moves to the back row.
While their nearest contenders are counting the wounded, the unbeaten Chiefs have made sweeping changes to play the Rebels including a switch for fledgling All Blacks fullback Damian McKenzie to fly-half.
Under the New Zealand rugby set-up, the two-Test, 21-year-old McKenzie has been moulded as an understudy to Ben Smith and Dagg, but assistant Chiefs coach Neil Barnes said McKenzie "prefers to play 10" and has been given the chance this week.
Among the other changes, Solomon Alaimalo makes his debut on the left wing while Seb Siataga gets his first start for the Chiefs at hooker, but Barnes maintained his side have "a fair bit of respect for the Rebels scrum".
In Australia, the ACT Brumbies and NSW Waratahs clash in Sydney for the inaugural Dan Vickerman Cup, giving added significance to their deep-seated rivalry.
The trophy will honour former Wallaby Vickerman, who died last month. Vickerman played 20 games for the Brumbies between 2001-2003, before appearing 58 times for the Waratahs.
New South Wales Rugby chief executive Andrew Hore said the trophy will add further weight to what is already expected to be a torrid battle.
"Dan was one of those team mates who were admired by all that knew him and I know both sides will be wanting to take home the Dan Vickerman Cup," said Hore in a statement.
"It is another way for the rugby community to recognise Dan's contribution."
Africa 2 conference leaders Coastal Sharks play the Southern Kings in Durban while the Northern Bulls host Japan's Sunwolves in Pretoria.
The Golden Lions are at home to the Queensland Reds in Johannesburg and the Central Cheetahs head to Buenos Aires to play the Jaguares.