“This is very tough on Folau,” Highlanders head coach Tony Brown said in a statement.
“He’s been playing outstanding rugby for us this season and he must have been in consideration for the All Blacks with his performances in Sky Super Rugby Aotearoa and the Mitre 10 Cup.
“We are fortunate that we have an excellent replacement in Kayne Hammington who has been training hard for an opportunity, he is very experienced and knows our game well.”
Fakatava left the field after 50 minutes during the Highlanders’ 33-12 win against the Crusaders on Friday, but appeared to only be in mild discomfort.
Highlanders assistant coach Clarke Dermody confirmed on Tuesday that Fakatava’s knee was swollen and that he needed a scan, but the full extent of the injury will hit the club hard.
Dermody also revealed on Tuesday that form midfielder Thomas Umaga-Jensen broke a bone in his arm against the Crusaders and would be out for three months, while a fractured foot has already ended wing Freedom Vahaakolo's campaign.
Off-season recruits Fetuli Paea and Jermaine Ainsley both suffered serious ankle injuries before the season even began, while Dermody also said on Tuesday that the nature of Liam Squire's knee injury was “chronic”, explaining why he will miss the rest of the season.
The Highlanders have now called three extra players into the squad – Otago halfback Josh Arscott, Otago midfielder Josh Timu and Southland outside back Josh Moorby.
However, they will find it impossible to replace Fakatava, as the halfback had added another dimension to their play in 2021.
Strong defensively and powerful with ball in hand, Fakatava had formed a potent one-two punch with All Blacks No 9 Aaron Smith.
His form catapulted him into All Blacks contention, and the enormous growth in his game over the past 12 months was evident against the Crusaders last Friday.
Fakatava won one crucial ruck penalty on his own tryline and marshalled his pack cleverly, bring big men such as lock Pari Pari Parkinson into the game with his varied passing skills.
Fakatava recently re-signed with the Highlanders until the end of 2023, and the Highlanders see him as Smith's long-term successor.
“I have really enjoyed my time here and although there were other options, I really wanted to pay back the club that gave me my start,” Fakatava said in a statement after he re-signed.
“I have had the best halfback in the world as my coach and I feel very lucky to have had the chance to learn so much down here.
“I feel like a southern man now.”
The Highlanders will face the Chiefs in Dunedin on Saturday with at least two new faces needed in the starting lineup.
Scott Gregory must be a good chance of retaining his spot after a strong performance against the Crusaders, although he may well move into the midfield berth vacated by Umaga-Jensen.
That leaves the No 14 jersey open, with the likes of Ngantungane Punivai an option for the role if Brown doesn't recall Josh Ioane at fullback and move Connor Garden-Bachop to the wing.
The Highlanders will reveal their team at 12.30pm on Thursday.