ROBBIE Farah's Origin hopes have taken a hit after the veteran hooker was benched and injured in South Sydney's 20-6 loss to North Queensland.

After being assured this week by coach Laurie Daley he would retain his place as New South Wales hooker if he was fit and firing, Farah was benched in favour of the livewire Damien Cook just before kick off.

He got on before halftime but left the field of play shortly thereafter with a back injury and did not return.

Cook didn't shine in the defeat, but he did have a couple of nice touches and pulled off a good cover tackle on a runaway Michael Morgan.

Farah has missed just one Origin match since 2012 but a slow start to the season with the Rabbitohs has him under pressure to retain his place.

Peter Wallace has been sounded out as a possible replacement - the Panthers rake will get an excellent chance to press his claims when he takes on Queensland skipper Cameron Smith on Saturday night.

The Gold Coast's Nathan Peats is another possible contender, but he's only played one match this season due to injury.

The Roosters, meanwhile, lost Dylan Napa on Friday night to a suspected ankle syndesmosis injury in their 18-12 loss to the Sea Eagles.

Napa came off in the 18th minute at Allianz Stadium and did not return. He is expected to have scans on the weekend.