Barrett sustained a significant injury to the structures supporting his big toe while playing in the Crusaders internal game on Saturday 13 June.
After consultation with a foot specialist, it has been determined that Barrett will undergo surgery. Exact return to play dates are uncertain at this stage, but he will need a sufficient amount of time to recover.
Alex Ainley has joined the Crusaders squad as injury cover for the remainder of the competition, while Codie Taylor will take over the captaincy reins.
Meanwhile, the Blues will be without livewire forward Tom Robinson for up to six weeks, after the 25 year-old underwent surgery on Monday.
Robinson suffered a meniscus tear in the Blues’ win over the Hurricanes in the opening round and scans revealed he needed a small operation to clean cartilage from his knee.
There’s still hope the hard-working utility will be back for the final rounds of Investec Super Rugby Aotearoa.