Sam Williams on bench for Raiders return as Canberra sweats on Austin

The Canberra Raiders have recalled halfback Sam Williams to the game-day squad as the Green Machine sweat on Blake Austin's availability to play on Sunday.

Austin has been named at five-eighth to play against the St George Illawarra Dragons in Mudgee despite injuring his ankle last weekend, with Williams joining an extended bench for the first time since April 5.

It sets the stage for a three-way halves tussle to partner Aidan Sezer as the Raiders set their sights on claiming their biggest scalp of the season.

Williams hasn't played since damaging the medial ligament in his knee against the Canterbury Bulldogs in round five, but was the Raiders' first-choice No. 7 for the opening rounds.

The off-contract Austin has hit top form in his absence, while Ata Hingano was thrown into the halves when Austin limped off the field last week.