Penrith officials met with the NRL on Tuesday to hand over their report - including witness statements - to the game's governing body, and it's hoped the perpetrator who called Inglis a "black dog" will be identified by the end of the week.

Rabbitohs players have rallied around Inglis, who has previously been at the centre of a racial slur from an online troll in 2013 and had Andrew Johns apologise to him over another incident in the 2010 NSW State of Origin camp.

"Greg himself is fine," Souths captain Sam Burgess said.

"Greg has been great. He's not kicked a fuss up, he's not said too much about it, it's not causing a distraction among the team.

"Obviously what happened out there at Penrith is not what we want in sport across schools or anywhere really, across the country or world.

"We're disappointed but Penrith are doing everything they can to find a result. We trust they'll do the right thing but Greg is okay."

NRL chief executive Todd Greenberg threatened to "throw the book" at the culprit on Monday, saying they'd "no longer be welcome back in the game".

Inglis was jeered by members of the Panthers Stadium crowd when he left the field for a concussion check early in the second half, but it's understood the alleged slur occurred at fulltime as Souths went up the tunnel following the 18-14 loss.

Meanwhile, Inglis is recovering well from the concussion and is expected to be fit to take on Manly on Saturday night as part of the ANZ Stadium double-header.

He's also expected to remain at centre as Souths try to turn their 0-2 start around.

Inglis spoke last week about wanting to return to fullback as part of a reshuffle in place of Alex Johnston once he returns to full fitness, but the Rabbitohs don't want to rush the Kangaroos superstar.

"He had a big year off with the knee injury, and it's a big injury," hooker Damien Cook said.

"We've got to let Greg get back into the game and get his confidence up. He's very good in the centres. That's why he gets picked there for State of Origin.

"Alex is doing a good job back there. The team is going to get better as well, and once Greg gets confidence and starts playing his best footy we all know what he can do."

Australian Associated Press