The impact of injuries and of efforts to minimise them will become more obvious as Super Rugby nears the midpoint of its regular season.
All Blacks first-five Dan Carter, Springboks winger Bryan Habana and Wallabies speedster Digby Ioane are among a growing group of topline players ruled out of action by injuries as coaches are forced to ring other selection changes to more evenly spread the workload among their squads.
Only one team - the high-flying Bloemfontein-based Cheetahs - has so far named an unchanged lineup, making depth and the ability of teams to adapt to changes in lineups and combinations key issues as the pressure of the tournament weekly increases.
Perhaps most hard hit by injuries are the Cape Town-based Stormers, who led last season's tournament throughout the regular season but are currently in 11th place with two wins from six matches ahead of a critical derby against South African conference leaders the Sharks.
First-five Elton Jantjes, who has aggravated a knee ligament strain, is the latest to join the Stormers' lengthy injury list and has been replaced for Saturday's match by Gary van Aswegen.
"He could be ready for the first tour match (against the Hurricanes in Palmerston North on April 26)," coach Allister Coetzee said. "It's not torn. It's an old injury which he aggravated."
Springboks flanker Schalk Burger remains in hospital two weeks after contracting viral meningitis following an operation for a calf injury. He was listed in a stable condition.
Among other Stormers' injury concerns: Jaco Taute is out for the rest of the season and will undergo surgery to repair a knee injury; Rynhardt Elstadt (shoulder) and Don Armand (ribs) both sat out training this week and will miss the Sharks match; Tiaan Liebenberg (elbow) will miss the Stormers' tour to Australia and New Zealand; Ruan Botha has a broken ankle and will be out for three weeks; flyhalf Peter Grant will miss the overseas tour with an ankle injury; Gerhard van den Heever will miss the Sharks match with a knee injury but will be considered for the tour; Deon Carstens is still recovering from a back injury and Bryan Habana is expected to be fit to tour as he continues his recovery from a knee injury.
"I don't want to get too carried away about his exact return date but he will definitely make the tour," Coetzee said.
"It's vital that we get our campaign back on course with a positive result from the match this weekend."
The Sharks also have injury concerns. Winger Odwa Ndungane has a hamstring strain but has been named on the bench, allowing 19-year-old Sean Robinson to make his debut.
Jacques Botes suffered a broken arm in the Sharks' match against the Crusaders last weekend and has been replaced by Ryan Kankowski. Jean Deysel also returns on the bench after overcoming an ankle injury.
Carter was due to rejoin the Crusaders for their match this weekend against the Western Force after missing their two matches in South Africa to be present at the birth of his first child.
He suffered a hamstring injury in training and has returned to New Zealand, likely for a three-week spell on the sideline.
Israel Dagg has been named at fullback but has been unable to start the Crusaders' last two matches because of a hamstring strain.
Corey Flynn also returns at hooker for his 250th first class match as coach Todd Blackadder makes four changes to his lineup for the last match of his team's overseas tour.
Jordan Smiler will make his Super Rugby debut on the blindside flank for the ACT Brumbies, who have made six changes to their lineup for Friday's match against the winless Highlanders at Dunedin.
Matt Toomua joins the Brumbies' lineup at flyhalf, Andrew Smith at outside centre, Stephen Moore at hooker and Sam Carter at lock. Tevita Kuridrani and Pat McCabe have been named on the bench while Scott Fardy has been ruled out with an ankle injury.
"Jordan has been with us for some time now and understands all the structures and systems in place. He'll slot in nicely on Friday night," coach Jake White said.
The Highlanders also have six changes with prop Ma'afu Fia taking over from Chris King, Jarrad Hoeata rejoining Brad Thorn in the second row, TJ Ioane making his starting debut at flanker, Japan scrumhalf Fumiaki Tanaka having his first start along with flyhalf Hayden Parker and Phil Burleigh starting at center.
Winger Rod Davies will make his first start of the season in the only change to the Queensland Reds who take on defending champions and current tournament leaders the Chiefs at Hamilton on Saturday.
Ioane has a knee injury but is expected to be fit for next weekend's match against the Brumbies. Radike Samo (knee), Saia Faingaa (neck), Luke Morahan (ribs) and Nick Frisby (ankle) will miss Saturday's match but are also expected to return for the Brumbies match.
Springboks Akona Ndungame and Flip van der Merwe return to the starting lineup for the Pretoria-based Bulls who face Cheetahs on Saturday. Ndungane has recovered from an eye socket injury sustained against the Crusaders four weeks ago while Van der Merwe suffered a chest muscle injury in the same match.
Jurgen Visser will take over at fullback from the injured Zane Kirichner.
"We are happy with the squad rotation and with a couple of stalwarts still out injured, it has given some of our youngsters good opportunities to play," coach Frans Ludeke said.
The Cheetahs are on a four-match winning streak.
Which two NZ teams look the most likely to make the Super Rugby playoffs?