The 31-year-old, however, is not expected to require surgery and should be fit again for the tail end of the Super Rugby season, with the Crusaders leading the competition and strong favourites to win a third successive title.
"The good thing is it doesn't require surgery, so it will be a good rehab process," Crusaders assistant coach Jason Ryan told reporters. "It's obviously a relief for everyone.
"It was touch and go there for a bit. Get him back in a month, all going well.
"He's got a good rehab plan for the next four weeks, and all going well that's when he will return to play."
Franks, a cornerstone of the All Blacks scrum since he made his debut in 2009, was injured in the Crusaders' 36-14 victory over the ACT Brumbies on April 6.
The tighthead prop wrenched his shoulder in the game and then uncharacteristically pulled out of a scrum just before it engaged, saying "nup" and immediately trudged towards the sidelines.
Crusaders coach Scott Robertson had said last week that Franks needed a second scan on the injury, which caused some consternation amongst All Blacks fans ahead of the Rugby World Cup in Japan later this year.
Franks has earned 106 caps for the All Blacks and was a core member of the side that won the Rugby World Cup in 2011 and 2015.
All Blacks coach Steve Hansen, however, has capable replacements including Nepo Laulala, who has 17 caps and cemented himself as the first choice when Franks had surgery on his Achilles tendon in 2017.
Ofa Tuungafasi has also played 26 tests for the national side, while the Otago Highlanders' Tyrel Lomax, who made his debut against Japan last year, has been the form tighthead prop among New Zealand's Super Rugby teams this season.
Hansen also received some good news at the weekend with his first-choice blindside flanker Liam Squire, who has not played at all this season, and winger Waisake Naholo expected back for the Otago Highlanders within the next two weeks.
(Reporting by Greg Stutchbury; Editing by Amlan Chakraborty)
