Canterbury coach Des Hasler has called out his underperforming outfit after producing yet another insipid performance against South Sydney.

In arguably his most scathing assessment of his side this year, Hasler described their 28-14 loss to the Rabbitohs as "flat", "undisciplined", and "unacceptable".

Their latest failures means the Bulldogs have now lost 10 of their past 12 matches, increasing the darkening cloud over Hasler's tenure at Belmore.

"I gotta say, we looked a bit flat," Hasler said after the loss.

"Scenarios where we refused to buy into just managing a game possession-wise and we come up with undisciplined passages in our play, and we come up with basic errors in our game."

Twice the Bulldogs looked swung momentum to their favour with tries at ANZ Stadium, but twice they turned the ball over on the kick-off and conceded points.

"We scored in the first set just after halftime, 14-8, you think momentum's going our way and then we drop it from the kick-off," he said.

"Next minute it's 26-14 and we don't see the ball for another eight, nine sets. And we didn't do it once - we did it twice. So at a first grade level, that standard of football is unacceptable."

However Hasler refused to believe his team had thrown in the towel on their season, and denied he had also begun to doubt faith in his ability to coach.

This season is the first in 13 years a Hasler-coached side has missed the finals.

"There's no doubt in what we're doing. There are parts in our game where we got into a bit of grind, we got into a bit of footy with them," he said.

Bulldogs captain James Graham was at a loss to explain his team's form.

"The reality of the situation is setting in, it's there for all to see. But if I knew the answer, I'd tell the boys. I just can't figure it out at the minute," he said.

The Bulldogs are sweating on scans for departing star Josh Reynolds, who retired midway through the first half with a calf strain.

"He's done a calf, he'll be sent for scans. Calves don't always have the happiest of endings, do they? It must be bad for Josh to come off the field," Hasler said.

- AAP