All Blacks star in hospital with spinal infection

His absence is a blow for the defending champions, who are sixth on the table after a slow start.

"His return to rugby beyond (the ⁠season) remains unclear and ‌will ​be guided by further medical advice," the Crusaders said.

Williams ​said he had ‌a sore back for a couple of weeks ​before going in to hospital for scans.

"I'm feeling gutted, but I'm also grateful that the news ​isn't ​as bad as ​what it could be," he ‌said.

"I've been told I'm going to make a 100 percent recovery, so I'm thankful for that."

The All Blacks start the Test season in July with matches ​against France, Italy and Ireland as part of ​the inaugural Nations ⁠Championship.