The Warriors are confident Shaun Johnson has not ruptured a pectoral muscle after he failed to finish the club's 38-18 loss to the Sydney Roosters.

Johnson appeared to battle through significant pain in the Warriors' fourth straight defeat, before leaving the field with around 14 minutes to go.

The halfback's injury comes just days after Roger Tuivasa-Sheck tore his hamstring at Warriors training, leaving him out for up to six weeks.

Any serious pectoral injury would leave large question marks over Johnson's future.

The 34-year-old is off contract at the end of this year, and a ruptured pectoral would have the potential of ending his season early.

But after leaving Johnson on the field for the majority of the game, coach Andrew Webster is not that concerned.

"If there was going to be an issue there or going to end with a ruptured pec, I wouldn't have had him stay on the field," Webster said.

"I don't know if he's good for next week. He battled on at halftime. It was a tough conversation.

"He said 'I want to go and fight here', and I'm really proud of him, the way he wanted to do that.

"But yeah, as a result of where he's at next week or anything like that, or how long if he's out at all, I don't know yet.

"He's very sore at the moment. It started hurting him when he was passing the footy and things like that."

The Warriors are hopeful of having five-eighth Chanel Harris-Tevita available next week to replace Johnson against Penrith, if needed.

But what is clear is the club must turn things around fast.

While they were the fairytale story of the NRL last year, 2024 has quickly turned into a horror show with three victories from their opening 10 games.

A loss next week to the three-time defending premiers Penrith would leave their season firmly in the balance, with serious doubts over whether they can recover.

The Warriors did well to keep the scoreboard somewhat respectable on Sunday at Allianz Stadium, but were never in the contest after conceding four tries in 10 minutes early.

"We're lacking confidence," Webster said.

"I'm not going to gloss over it. It starts with me. I've go to find a way to get these boys confident and believe in how good they can be.

"Because when something went bad there early, it took a while for us to really put our feet in the ground and stop it

"It was a juggernaut coming at us and we (should be) good enough to stop it, add resistance and turn them away."