Nabura (26) injured the anterior cruciate ligament in his knee at training last week and, after examinations over the past few days, medical staff have decided he needs an operation which will end his season.
The recovery period for most ACL injuries is nine months so Nabura is unlikely to be sighted at all in the 2019 season.
The Highlanders are mulling over a replacement and will make a decision on who to bring into the squad in the coming weeks.
Highlanders assistant coach Mark Hammett said it was a big disappointment for Nabura, who had been working hard in pre-season.
Nabura scored three tries for the Highlanders in the game against the Waratahs in Alexandra on February 1 in what will be his only appearance for the side this year.
He was just running at training, cut in on the angle and injured his knee. He is likely to have an operation next week.
Hammett said Nabura had prospered in the Highlanders environment since joining the team for the 2018 season.
"He was looking really good and had become a special part of the team. Just considering where he had come from at the start of last year to this year he had made huge growth. So it is disappointing for him,'' he said.
Hammett said that was the only major injury worry.
Tighthead prop Siate Tokolahi who has been coming back from a knee injury is available for selection for Friday night's opening game against the Chiefs in Hamilton.
Hammett would not be drawn on who the coaching team would name at first five-eighth. The side is due to be named tomorrow.
The pre-season had gone well and now was time to get the season under way, Hammett said.
"We are further ahead than last year but you always have to be. If you stand still then you have gone backwards.''
As for the playing of the game, Hammett said teams last year held the ball for longer so there were longer periods spent on defence. He was not expecting much change.
"Often in World Cup year there is not a lot of changes from a law perspective. We will see how the season progresses. We will get a pretty good feel with that in the first three weeks.''
The Highlanders lost both times to the Chiefs last year, including a heavy defeat in Suva. Overall, the side struggled to gain victories away from home, winning just three games away from Forsyth Barr Stadium.
"It is a fact we were not good away from home. That is something we have really concentrated on through our leadership group and through our preparation and how to do it better.
"Our weeks were pretty good last year but it is more to do with the back end of the week. Just not as spot on as we could.''
The Chiefs lost to the Blues and beat the Reds in pre-season games.
Hammett said he did not take much notice of those games.
"In all the years I have been coaching I have realised you do not pay any attention to pre-season, to be fair. You may look at structures and what they are doing in defence.
But it is more about expecting the very best and over the past couple of years we've had the very best out of them. We are excited about the challenge ''