Alex Johnston's try-scoring binge at ANZ Stadium ended in pain as South Sydney crushed the Warriors 36-18 on Friday night.
Johnston crossed three times to take his haul to 22 for the season, but limped off the field with a right hamstring injury in the game's dying minutes as he completed his hat-trick.
The Rabbitohs flyer crossed twice in the second half as Souths piled on 24 points in 20 minutes to overturn a 18-12 deficit in front of just 6,213 fans.
However he will go for scans on Saturday as the Bunnies' injury toll continues to mount.
"He's probably got something there and we'll have to assess that," coach Michael Maguire said.
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"It's really unfortunate because he's been playing some great footy and is looking at records around the club with tries."
The hat-trick took his streak to 17 tries in his past seven matches at ANZ Stadium, the best run of any player at any ground since 1980, according to Fox Sports Stats.
His season figure of 22 also tops the mark of 21 he set in his debut year of 2014.
It could also heap pressure on Michael Maguire to keep him at fullback next season, even with Dane Gagai's impending arrival and Greg Inglis' return from a knee injury.
"I haven't even thought about that yet," Maguire said.
"We'll work our way out as it comes. I'm just pleased for AJ that he has been able to find form as a fullback."
The result will be a bitter pill to swallow for the Warriors who could have lost representative stars Kieran Foran (back) and Jacob Lillyman (bicep).
Lillyman's now out for the season, while Foran is in doubt for his last two games at the club before he heads to the Bulldogs next year.
"It has been a tough year for (Foran)," coach Stephen Kearney said.
"If it's not one thing it's another."
The defeat marked the Warriors' seventh in a row since round 16.
Roger Tuivasa-Sheck was a rare shining light for the visitors as he crossed twice, while lock Simon Mannering was crafty in attack and resolute in defence.
