The Cronulla Sharks have lost second-rower Tony Williams for the season with a knee injury after playing just one NRL game for the club this season.

Scans have revealed Williams suffered a torn ACL after twisting awkwardly in a tackle while in action for Tonga against Fiji on Saturday.

"He has a torn ACL and will need surgery. He will see a specialist in the next few days to determine the best course of action," Sharks physical performance manager Andrew Gray said.

Williams made his only appearance in the Sharks' NRL side in Round 9 when he started the game and scored a try after spending the early part of the season playing for Cronulla's feeder club the Newtown Jets in the Intrust Super Premiership.

Read more at sharks.com.au