South Sydney Rabbitohs speed demon Alex Johnston is happy to give the famous cardinal and myrtle No.1 jersey back to Greg Inglis whenever his skipper is ready, despite passing up fullback roles on offer at rival clubs last season.

Johnston played arguably his best game at the back for Souths in their 34-6 trouncing of Manly Sea Eagles last week, and will remain there for a while yet as Inglis returns from an ACL rupture via left centre.

While coach Anthony Seibold has indicated it will be Inglis's call on if and when he reclaims the No.1, it was his season-ending injury that gave Johnston a serious crack at his preferred fullback position last year.

But with Cody Walker also tried at the back and football manager Shane Richardson describing Johnston "as a winger who can play fullback", fierce rivals St. George Illawarra Dragons came calling with their own No.1 spot for him after Josh Dugan's move to Cronulla.

At one point the Sharks also discussed the off-contract La Perouse junior as an option before he tied his future once more to the only club he has ever known, re-signing with the Rabbitohs until the end of 2020.

"At the end of the day there was a couple of clubs, but I thought the best opportunity was staying at Souths," Johnston told NRL.com.

"I love playing for Souths so the decision was made easy. I still find that I have a good opportunity to play fullback here.

"I love playing here, it's my junior club and I love playing with all the boys here. That's what made the decision easy in the end."

Johnston eventually committed to Souths after they bumped up an initial offer that would have seen him paid largely as a winger.

His blistering finish 2017 proved the faith from both parties well-placed, as the 23-year-old returned to fullback late in the year and produced six tries in three consecutive wins.

After a rocky start in round one's loss to the Warriors, when Johnston carried a lingering rib cartilage injury into the game, he hit his straps against Manly with a 95-metre runaway try, two assists and several quality reads defending Daly Cherry-Evans' short kicking game.

Johnston is the first to admit his positional play at fullback is a work in progress.

His showdown with re-energised Canterbury-Bankstown Bulldogs counterpart Moses Mbye looms as a fascinating subplot to the latest edition of the Good Friday showpiece game, with Mbye proving one of the most dangerous ball-runners in the NRL since shifting to fullback.

But by the same token Johnston declared has no issue to continue his development on the wing – where he has bagged an impressive 59 tries in 63 games – should Inglis switch out of the frontline once more.

"Really, it's what's best for the team," Johnston said.

"At the moment I'm loving playing fullback and I'm just trying to do the best job I can with that by playing my best footy.

"If I have to go back to the wing in the future I'll happily do that. Greg can give me some tries, I'm sure he'd be good for a few no doubt.

"I'm feeling more comfortable at fullback for sure, and when I see what I think is coming, I'm then trying to get into position as quick as I can.

"It's something I am working on and will continue to work on, I've just got to be more consistent with it."