Garden-Bachop broke his wrist during Saturday's loss to the Chiefs in Dunedin.
He will be out of the game for 12 weeks.
Highlanders coach Tony Brown said it was a devastating blow for Garden-Bachop who has had several injury issues.
"He couldn't partake last year because of a back operation, then he played one game for Wellington and dislocated his elbow. It's a frustrating time for him," Brown said.
"He's just starting to play really well and get recognised as a quality rugby player. So, for him to not be able to play the rest of Super Rugby is a big blow for him, and a big blow for our team."
Garden-Bachop's loss follows that of lock Pari Pari Parkinson who has suffered a recurrence of an ankle injury. His ankle had been scanned and it had not been bad news but they were taking a wait-and-see approach with it.
"The operation has flared up a little but there is no major damage," he said.
Brown took a positive approach to the injuries saying it was part of the game.
"Sometimes you get really lucky, and you get through a campaign with hardly any injuries. Then, sometimes, you get a dozen, which is about how much we've got.
“We've had season-ending injuries that have put us under real pressure now”
That provided a chance for new players to make their mark, especially in the Australian part of the competition.
The immediate focus was on the Blues who were a good side, he said.
Players enjoyed taking on good sides and it was easy to get players up for a game in which they were the perceived underdogs.
For the Highlanders, it would be about getting the parts of their game right that they hadn't achieved last weekend.
"We're looking for a major improvement in our intensity and how we go about our work," he said.
"If we can keep the ball in play, and keep the ball moving it is going to be an entertaining game to watch," he said.