Crusaders prop Owen Franks will be sidelined for the next four weeks with a shoulder injury.
The All Blacks front-rower hasn't played for the defending champions since the win over the Brumbies in early April and is now expected to return near the start of the Super Rugby playoffs.
The MRI results indicated Franks wouldn't require surgery for what assistant coach Jason Ryan described as a "small tear" in his shoulder.
Ryan admitted the news came as a "relief", as they'd been braced for a far more dire diagnosis.
"It's obviously a relief for everyone," Ryan said."It was touch-and-go there for a bit.
The 106-test international joins a growing list of injured All Blacks players, which also includes Liam Squire, Dane Coles and Damian McKenzie.
Michael Alaalatoa will likely continue to start in place of Franks, while Oli Jager provides cover off the bench.
Also out of action for the Crusaders against the Sharks on Friday will be Sam Whitelock and Ryan Crotty - both absences part of the All Blacks mandatory rest policy.
Crotty was forced from the field during the win over the Lions on Friday with a suspected concussion. He passed the subsequent head injury assessment (HIA), but the Crusaders coaches decided to err on the side of caution and keep him out of further action.
Ryan confirmed the midfielder had already been earmarked to miss this weekend's fixture.
Meanwhile, hooker Andrew Makalio will return to full training this week, as he overcomes a minor calf issue.
With the Crusaders scrum at times exposed against the South Africans, All Blacks guru Mike Cron was on hand to provide a few suggestions at Monday's training.
"I just wanted to make sure we're getting everything right," Ryan said.
"He [Cron] is the best in the world, so why not invite him down here to have a look at what we're doing and make sure we're on top of things."
Join us at 7:30pm Friday for live updates of the Crusaders v Sharks Super Rugby clash.