PORT ADELAIDE captain Tom Jonas is backing Showdown specialist Robbie Gray to jump from the injury list to the 50th derby at Adelaide Oval on Saturday night.

Sidelined since suffering a knee injury in his 250-game milestone match on June 19 against Gold Coast at Metricon Stadium, Gray seemingly has just one box to tick - training on Thursday - to play in his 21st Showdown against Adelaide.

"You don't see too many Rolls Royces at SANFL level," said Jonas of Gray's right to walk directly into AFL selection after six weeks on the sidelines. "If he is right to go, he has the right to come straight back in.

"He is a superstar. He has done his bit.

"He is certainly capable; we know how much he loves the Showdown," added Jonas of Gray who has five Showdown Medals (2010, 2015, 2018 twice and 2019) in his collection. 

"He was moving pretty well last week. He will have to get through training again on Thursday and then that will be a decision (senior coach) Kenny (Hinkley) has to make. But we know he likes a Showdown. He is a player who rises to the big occasion. It would be great to see him out there.

"He has pretty well executed his rehab as specified. He was over in Melbourne doing his rehab running seasons, getting agility and plenty of more work into the knee. So it has progressed as planned there. It might just come down to the final few bits and pieces in the boxes he has to tick."

Port Adelaide players returned to training at Alberton on Tuesday after a two-week hub in Melbourne. Jonas described the Tuesday session as "pretty cruisey".

"With an exemption we able to come into the club, so it was a typical (start to a training week) with a little bit of weights, mobility, review and a bit of touch," said Jonas who will have another COVID test on Tuesday evening to satisfy SA Health protocols.

"It was good to get out of the house for an hour or so and see the boys."

Port Adelaide's long wait for reinforcements to come off the injury list is now creating a selection headache of the other extreme with more and more options to consider at match committee.

"There are plenty of blokes pressing on the back of SANFL form and returning from injury," Jonas said. "Robbie Gray is the obvious one. Tom Clurey is waiting in the wings. Joel Garner. Jackson Mead. Sam Mayes. Jarrod Lienert. Boyd Woodcock. They have all found themselves missing out because others have come back."

Port Adelaide's form is seen as "building" with stronger ball movement and greater command of forward-half territory, more so with the return of key personnel in recent weeks.

"It is pretty positive; we continue to build," Jonas said. "We are adding to our offence. We are controlling our own destiny. We go into each week knowing it is very important we play strong footy and we keep winning.

"We have found a better balance (within the gameplan). We were struggling to score for a little while. We have some key parts back to add to that excitement. Put Connor Rozee, Xavier Duursma and Zak Butters back into any side and you are going to move the ball a little bit better. 

"We are finding that balance and that has challenges defensively, but at the moment it is working for us."

"Showdown obviously is a very exciting game, regardless. There is a lot of the end of it for us - and controlling our destiny is exciting for us."

Port Adelaide is looking to take a 26-24 lead on the Showdown ledger by winning four derbies in a row - and sweeping the Crows for the sixth time and first time since 2013.

"We go into any game expecting to win, so nothing changes," Jonas said. "There is a little bit extra on the line (with Port Adelaide's top-four aspirations). Every Showdown has excitement and hype. For us, it is about four points. And an important four points.

"We have gone into the past couple (of Showdowns) with favouritism and it has panned out like that. But they certainly have not been easy games. They have been tough and hard fought. 

"You have to go into every game expecting teams to be at their best. Otherwise, you would be foolish. 

"It is nice to go into the Showdown with strong results, but the Crows are playing some really strong, competitive footy and they will go out there to have an absolute crack. It will be a typical Showdown. It will be about the contested footy and on anyone's day they are good enough to push you the whole way. We need to be ready."

While Sydney and Fremantle in recent weeks have worn heritage jumpers, Port Adelaide will not wear its traditional black-and-white bars as the club wishes for Showdowns. The AFL continues to deny the club its request to establish the guernsey as a derby jumper.

"It is disappointing," Jonas said. "It is great those teams get an opportunity to put their heritage on display. We would love to be able to do that. But the decision was made in April that we would not be able to wear it this year and we now leave it to (chief executive) Matthew Richardson and (president) David Koch to work on that in the background.

"It is a great symbol for our club and our people and we are all disappointed we can't put it on display. But the conversation has been had over and over again and we are just focussing on the footy now. Kochie and Richo will sort that out, but we are not giving up the fight to wear the bars again.

"They are great kits (at Sydney and Fremantle); you love those throwbacks to another era and it is very nostalgic and has great memories. Let's hope there is an opportunity for us."

Still in question is how many fans will be allowed to Adelaide Oval to see Port Adelaide as the away team in the derby.

"I would much prefer to have fans there," Jonas said. "They are great for the game. They bring great energy and personally I do not mind a few boos here and there. It gives you a bit of extra fuel for the fire."