Canberra Raiders’ premiership aspirations have taken a huge hit, with playmaker Blake Austin potentially out for the rest of the NRL season with a hand injury.

The five-eighth will undergo surgery on Thursday after a mishap during a defensive drill at training on Wednesday.

A statement from the club said Austin will be sidelined for an “indefinite period”, perhaps the season.

“It was a very simple accident and very unfortunate for Blake,” coach Ricky Stuart says.

Third-placed Canberra are riding an eight-game winning streak but are only two-from-five without Austin this season.

Sam Williams has been drafted to partner Aidan Sezer in the halves for Saturday’s clash with Manly at Brookvale Oval.

“This will challenge us and everybody has to buy in and assist in picking up the slack,” Stuart said.

“We know (Williams) will do a great job for us.”

The Raiders are a chance of securing a top-two berth and a home final with wins over the Sea Eagles and Wests Tigers in the last round.

Certainties to finish in the top four, they last played finals footy in 2012.

Williams was halfback in the side, which was knocked out in the second week by South Sydney.