In a classic case of less is more, Keary has almost halved the amount of times he touches a ball during the game - and some would argue doubled his effectiveness - in a curious transformation from rejected Rabbitoh to reborn Rooster before the blockbuster against his old buddies on Thursday night.

The 25-year-old crossed the bitter Anzac Parade divide and has looked anything but a bit-part player that statistics uncovered by Champion Data suggest he has been in the opening three rounds.

Given a mandate to concentrate on his running game, Keary has averaged a paltry 23.33 possessions a game over the first three matches as the unbeaten Roosters charged to the top of the table.

It is a far cry from the 41.9 handles he averaged when wearing the cardinal and myrtle at the Rabbitohs in 2016.

And so sparsely has he touched the ball - while seemingly being so dangerous every time he's had it - there is no other halfback or five-eighth across the 16 NRL clubs who has been in possession as infrequently during the first three rounds.

Only the Panthers' Te Maire Martin (24.33) and Raiders' Blake Austin (25) compare to Keary in terms of touches a game - a far cry from the NRL's money men Johnathan Thurston (64.33) and Shaun Johnson (56.33) who have the ball glued to their hands when in attack.

The simplicity of Roosters coach Trent Robinson's mandate to Keary has no doubt helped him recapture his lethal running game, with the tricolours' No.7 Mitchell Pearce (54.66 possessions a game) doing the bulk of the ball handling.

While Keary, who combined with Adam Reynolds to lead the Rabbitohs to a drought-breaking premiership in 2014, has been in the headlines all week before returning to ANZ Stadium, it hasn't worried Robinson.

"I expect nerves from every player to get prepped each week, but Luke's a pretty cool cat," Robinson said. "I don't expect anything different from him this week.

"It's important enough to have the conversation [about playing your old club], but the guy's played lots of big games and he is a cool cat. He knows how he wants to play.

"It's hard to stop the feeling of playing your old team so that does come up. But he's working so hard on trying to get our stuff right. I'm sure it will be there - he's human - but we're still working on trying to find our best combinations and get our own footy right."

Which can also be said about the Rabbitohs, whose second-half surges have seen off Manly and Newcastle in the past couple of weeks.

The majority of Michael Maguire's squad still share a strong bond with Keary, who famously confronted Rabbitohs' owner Russell Crowe during a pre-season bonding camp at the Hollywood actor's Coffs Harbour property before last season.

Never forgotten: Sam Burgess, Luke Keary's teammate at Souths, still has a lot of respect for the new Roosters five-eighth. Photo: Getty Images

"I've got a lot of time for Luke, what we did and achieved in our time here," said Rabbitohs captain Sam Burgess, whose locker was adjacent to Keary's at Redfern. "Off the field we helped each other out with a few things. You never forget those times.

"I've got a lot of respect for Luke and I like seeing him do well. This is the week where I'd like to see him do not so well, but he's a good bloke. Luke's a competitor every week and you'll struggle to find a game where he's not turned up. He'll be ready for a big game on Thursday."

Pearce's early pitch to reclaim his NSW jumper from the Rabbitohs' Adam Reynolds will be one of the subplots of the clash between the two great rivals, but the Keary-Cody Walker showdown is also sure to attract interest.

Burgess and Keary have been trying to organise a game of golf for weeks and Rabbitohs rake Damien Cook joked the banter with their former feisty five-eighth had subsided in recent weeks.

"He was a premiership winner and a lot of the boys in that team were sad to see him go," Cook said. "He was a good mate of mine - and still is - but these things happen in footy and you have to move around to different clubs.

"Like any good halfback he's a good niggler and I'm sure there will be a few laughs and a few shots between a few players from both teams."