South Sydney veteran John Sutton will undergo scans this weekend after injuring his bicep in Friday night’s 20-6 loss to Penrith.

The Rabbitohs stand-in skipper came off late in the second half after copping a knock to the arm and failed to return to the field.

Prop David Tyrell was also stretched off after being knocked out in a head clash with Penrith counterpart Nigel Plum, but coach Michael Maguire said “he’ll be fine.”

Sutton, who missed almost two months earlier this year with a broken jaw, wasn’t overly concerned with the injury after the game but said he would get x-rays to diagnose the damage.

“I just felt something funny in my biceps,” he said post-game.

“It doesn’t feel too bad but I’ll just have to get scans done and go from there.”

The injury to Sutton compounded a disappointing night for the defending premiers, who rarely threatened to steal the game from a Panthers side that led from start to finish.

Down by just eight points at the break, the Rabbitohs let themselves down with an uncharacteristic 67 per cent completion rate in the second half that left them camped on their own tryline.

In fact, they didn’t get on the scoreboard until the 73rd minute mark, when winger Joel Reddy latched onto an Adam Reynolds crossfield kick.

“We put a lot of pressure on ourselves,” coach Michael Maguire said.

“We had to defend for long periods of time and allowed Penrith to attack our line and they were able to find a way across the line.

“There were a lot of fundamental little things around the game plan which failed us.

“We didn’t spend much time in their end of the field in the second half. You have to be able to build pressure by getting down the other end and spend some time down their try-line like they did to us.”

It was the second time in three weeks South Sydney scored just six points, leaving the competition heavyweights with plenty of soul searching to do during next week’s bye.

“It’s going to be a good two weeks to prepare for our next game and get our bodies in the best possible condition. We’ll be working hard at training to turn it around,” halfback Adam Reynolds said.