It's the story of how Walker and Latrell Mitchell began as rivals debuting in the NRL against each other and now have a bond so strong it is helping fuel South Sydney's finals run.

Souths received a massive boost on Wednesday ahead of Thursday's NRL grand final rematch against Penrith with Mitchell cleared of a groin injury.

The difference the fullback has made for Souths since his return from injury in round 16 has been clear.

Once struggling for consistency, the Rabbitohs have become the form team over the past two months with a 6-1 record.

A win against an understrength Panthers would keep them well in the top-four hunt, with clashes against North Queensland and the Sydney Roosters to come.

What also can't be understated is the influence Mitchell has had on Walker.

In the past seven matches, Walker has bust almost as many tackles as he did in the first 14 of the season.

The Bunnies' five-eighth has his bounce back.

"Obviously teams fear Latrell," Walker said.

"You have to number up on him because he's hard to handle one-on-one. He is quick for a big guy.

"He breaks a lot of tackles and just adds another another attacking threat."

While the presence of Mitchell in the Rabbitohs' attack often gives playmaker Walker more room to work, the pair are also linking up regularly again.

As far as Walker is concerned, that comes as much from instinct as from training.

"It's hard to explain how it works, because it's just one of those things that we anticipate what the other is going to do," Walker said.

"We talk about different game plans and whatnot ... but I wouldn't say a lot of it is thought (out).

"I might say 'the centre might do this..or this is a play that we can do'.

"Or just hitting him on the run, he will just say something to me as he's running out the back.

"And I know what play is on. You can't really explain it."

It's partly due, Walker believes, to a strong bond the pair share.

They debuted against each other in the opening round of 2016, Walker as a 26-year-old finally getting his chance at Souths and Mitchell an 18-year-old prodigy for the Sydney Roosters before becoming teammates when Mitchell joined the Rabbitohs in 2020.

"Two totally different stories ... It's crazy," Walker said.

Both men have developed into role models and leaders for the Indigenous community, and now hope to play their first finals series together this year.

"We spend a fair bit of time off the field together," Walker said.

"We're pretty close in that sense, so we have that mutual respect for one another.

"I admire that the person he is. He is such a beautiful person on and off the field.

"And what he's been able to achieve in the game at such a good age, you just just admire that about him."

Australian Associated Press