The Parramatta try-scoring sensation was reportedly struck down with a mysterious infection that led to his return to Sydney for expected urgent surgery.

The cult winger's manager Cameron Phelps said the Fijian international initially complained of discomfort with his hand before leaving for Fiji, but a series of X-rays and medical checks found nothing wrong.

However, after arriving back in Fiji, Sivo's hand "blew up" to such a worrying size, the 26-year-old was told to undergo immediate surgery.

"So we're still not exactly sure what is wrong," Phelps told Fox Sports.

"It could be a bite, who knows?

"Maika had hurt the hand before heading over to Fiji but, after undergoing some X-rays and stuff, there didn't seem to be anything really wrong with it."

Sivo flew into Nadi midway through November, having represented Fiji at the 2019 Oceania Cup tournament.

Australian Associated Press