The worst fears have been confirmed with Mitchell Barnett's season officially over.
While playing for the Warriors on Sunday, the NSW Origin prop landed awkwardly as he attempted to make a tackle on Souths half Jayden Sullivan
He immediately clutched at his leg and remained on the turf for over a minute as he was assessed by a trainer.
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"He's definitely done a knee injury of some description," Warriors coach Andrew Webster said post-match.
"We're waiting for scans, it's the boring old thing – but we honestly don't know what it is right now.
"There are different grades to each different injury, and until you look under the hood, you honestly don't know.
"He's in good spirits, we'll get back to New Zealand tonight and work it out tomorrow."
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However, scan results have since confirmed the forward did suffer an ACL rupture.
"Worst fears of a serious knee injury have been confirmed for inspirational Warriors co-captain Mitchell Barnett," the club noted.
"Scans today revealed he suffered a season-ending ACL rupture in his right knee in yesterday’s Round 13 clash against the Rabbitohs."
The 31-year-old was a key component of NSW's series opener win, recording 110 run metres and making 26 tackles, while being a key part of the Warriors ascension into the top-four.