Johnston has suffered through an injury-affected 2019, missing a month due to minor knee surgery before going down in his round 14 return with bone bruising in the same knee which required nine weeks out.

He made his comeback a fortnight ago but has been shuffled out to the wing while he regains full fitness.

He will make somewhat of a return to the No.1 position during Friday's qualifying final against the Sydney Roosters, though he and Adam Doueihi are expected to share the position after interchanging in the role during Thursday's captain's run.

"AJ isn't back where he wants to be at the moment but he's getting close to it," coach Wayne Bennett said.

"Adam has done a great job for us back there, we're confident in him and we'll mix it at different stages of the game."

A fulltime return to the fullback position is top of Johnston's priority list but he was happy to make a cautious return to first-grade via the wing.

"I won't know until I try," Johnston said when asked if he was capable of churning out an 80-minute stint at fullback.

"I want to play fullback. But there is the question of whether I can get through the game or not. It's something we need to take into account."

Johnston admits he is managing pain in his knee but is pushing through because of his desire to play finals football.

He was told by the club that he needed to get game time under his belt during the last few regular rounds or else they would have been reluctant to field him during the post-season.

"I'm still dealing with a few issues in the knee, it's not 100 per cent yet," Johnston said.

"But it's manageable.

"I had to come back when I did otherwise I might not have been able to play finals footy.

"Coming back on the wing was the best option, getting through 80 minutes was good, I'm definitely feeling more confident now."

Australian Associated Press