The Rabbitohs on Friday confirmed South Sydney's 2014 premiership-winning captain had entered a facility to undergo treatment to assist and support his mental health.

"On behalf of Greg and his family, we ask the media and the public to respect their privacy," a statement from the Rabbitohs said.

The 32-year-old former State of Origin and Test superstar played only two games this season before being forced into retirement by persistent injuries.

He took up a wide-ranging role with Souths, helping the team as an assistant coach and also working with the club's commercial division and charity arm Souths Cares.

But missing out on the weekly grind of an NRL season alongside his teammates has reportedly hit Inglis hard.

Souths coach Wayne Bennett - a strong supporter of Inglis's decision to hang up the boots - and the retired skipper's ex-teammates are rallying around the troubled star.

"The best thing I say about Greg is that he's getting the support that he needs," Bennett said.

"So that's as much as I want to talk about it. I don't want to elaborate on it. But that's the situation."

In an illustrious, 265-game NRL career, Inglis won two grand finals with Melbourne before leading the Rabbitohs to their first premiership in 43 years.

Widely considered a future Immortal, Inglis played 32 Origin games for Queensland, featuring in a staggering 11 series wins, and made 39 Test appearances for Australia.

But he was devastated to have missed the chance to lead his country after being stripped of the captaincy last year after being caught drink driving.

NRL chief Todd Greenberg told Channel Nine on Thursday night he was aware of Inglis's plight.

"I'm aware of some of the issues that he's facing and we're in contact with him and the club," Greenberg said.

"It will be a journey for Greg. But he's got a lot of support.

"He's got a lot of people around him, including all of us at the NRL."

This is Inglis's second stint in rehab, having checked himself into a facility for three weeks in 2017, after suffering a season-ending knee injury.

He said after his first stint that the game of rugby league needed to encourage players to speak about their feelings.

"It was taught at a very young age, toughen up and play on and just get on with it," Inglis said.

"I think we see ourselves as these fierce gladiators, men, warriors that take the field each week. Obviously we don't know what goes on behind closed doors.

"It definitely ain't weak to speak."

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Australian Associated Press