Inglis in doubt for Souths' clash v Manly

A 26-year-old rookie with just eight NRL games under his belt is on standby to fill the boots of South Sydney's superstar captain Greg Inglis on Saturday night.

With Inglis now in a race against the clock to overcome illness as well as injury, little-known Jacob Gagan trained in the centres for the Rabbitohs on Wednesday.

Inglis had been named to make his return from a shoulder complaint against Manly at Lottoland, but looms as a 50-50 prospect to play as Souths bid to remain unbeaten in 2019.

"I was meant to pick him up for training this morning and he sent me a message saying he was a bit crook," Inglis's centre partner and chaffeur Dane Gagai revealed.

"So he'll have the day off and rest and come in on Friday and do the captain's run and I guess we'll see what happens there."

Gagai remains hopeful his Queensland State of Origin skipper will recover in time and has full faith in Inglis's ability to perform despite minimal preparation if he does.

"You know what you're going to get with Greggie. He's competitive and he just needs to rest," he said.

"It doesn't really disrupt anything.

"One of the benefits we've got going here, which was a big key to our success last year, was the reserve grade boys going really pushed us at training.

"If anything happened and someone had to come and fill in, there was no doubts that that person was going to do the job.

"That's the same situation we're in here."

Gagan, a former Australian schoolboys representative, is in his second season at Redfern after failing to nail down a first-grade spot in four seasons at Newcastle and Cronulla.

He's also yet to make his top-grade debut for the Rabbitohs.