Bower, who has played 22 tests, has undergone surgery for an ACL injury suffered while playing for the Crusaders against the Reds last month.
Crusaders coach Scott Robertson confirmed the worst yesterday, saying Bower would miss the entire 2023 season.
"He had an ACL reconstruction. He’s mending well," Robertson said at a media conference in Christchurch.
Bower was a crucial part of the All Blacks squad last season, making 11 test appearances, the majority off the bench.
The injury will mean he will also be unavailable for Otago in the NPC, though he would have missed the campaign anyway had he been taken on the plane to France.
Bower’s Crusaders and All Blacks team-mate, Sevu Reece, suffered a similar fate earlier in the season.
The All Blacks’ depth at prop will be tested as yet another Crusader, Fletcher Newell, was ruled out of the Super Rugby season and it was uncertain whether he would be fit in time for the World Cup.
