Souths' Johnston in late NRL fitness test

Jaxson Paulo, who was subjected to cyber abuse after a torrid night against the Panthers last month, was not included in the 24-man list named on Tuesday afternoon.

Penrith have their own issues on the wing and have named Charlie Staines after Taylan May picked up a suspension in the sole change to the side that defeated Parramatta.

Parramatta, who face North Queensland on Friday in the other preliminary final, have named centre Tom Opacic as he aims to overcome a hamstring complaint in time for kick-off.

Bryce Cartwright has edged out Makahesi Makatoa on the Eels' bench with Brad Arthur retaining son Jake as the utility on his interchange.

The Cowboys are unchanged from the side which overcame Cronulla in week one of the finals.

The most intrigue, however, will centre around Souths who ruled out utility forward Siliva Havili (calf) on Tuesday and are confident back-rower Jai Arrow will be passed fit.

Jed Cartwright will take Havili's spot on the bench for his first game since round 20 and Johnston is hoping he won't be forced to watch Saturday's game from the stands.

"I'll be doing everything I can to get out there," Johnston said on Tuesday.

"I'll start running hopefully towards the end of the week.

"I'm not a doctor but I don't think you can needle it, it's a muscle sort of thing so it's physio, rest and ice up.

"It will be touch and go. I feel pretty confident the way it's recovered from yesterday to today. If it (stays on that) trajectory, I'll be right."

Arrow, meanwhile, has been battling his groin issue since first hurting it against Penrith in round 23, before aggravating it to its most painful point on Saturday night.

But he said he was not in any doubt for this weekend's preliminary final.

"I got a scan and it's pulled up all sweet," Arrow told AAP.

"It's just an ongoing thing that has been an issue for a couple of weeks now. I'll manage it through this week and be right to go Saturday."