ANDREW McLeod and Simon Goodwin have been ruled out of Sunday's showdown against Port Adelaide with injury, while NAB AFL Rising Star nominee Phil Davis has been dropped to make way for All-Australian defender Nathan Bock.

After spending five weeks on the sidelines recovering from knee surgery, McLeod was recalled to the team that upset Geelong last round and was also named in this week's squad.

However, the 340-game veteran failed to complete training on Friday morning and will be replaced in the side by forward Jason Porplyzia.

Coach Neil Craig said he was optimistic McLeod would miss just the one game.

"Andrew's knee blew up and it's not quite right, so he won't play on Sunday," Craig said on Friday.

"Andrew tried to have a run this morning, but it was pretty obvious early in the training that it (his knee) wasn't going to be good enough, so we didn't ask him to push through with it."

Goodwin was also named in the squad on Thursday afternoon, but has been forced out with an ankle complaint.

The skipper developed swelling in his ankle on Monday and football manger Phil Harper said the club doctors were mystified by the injury.

"Tuesday morning Goody got up and his ankle was really sore and he was wondering what was going on," Harper told Adelaide radio station 5aa.

"Wednesday morning was probably worse again and then today his ankle was worse again.

"They can't really put their finger on exactly what the problem is, so they're really worried about that one. It's always a worry when you don’t know what [the problem] is."

Goodwin has already announced that this season will be his last and McLeod is expected to follow his premiership teammate's lead over the next six weeks.

Craig denied the latest setback would spell the end of McLeod's career, but conceded swelling was an ominous sign for the 33-year-old, who has managed a serious knee injury for over a decade.

"Andrew had a reasonably big operation on his knee and it had been four or five weeks since he played, so for it to blow up after one game is not a good sign but we're still hopeful," Craig said.

"Andrew's still very positive about it and his attitude is superb - that he's committed to the year before he makes any decision and he'll play the year out to the best of his ability."

The club's other change, Davis, 19, earned his rising star nomination for his performance against Geelong forward Cameron Mooney and Craig said it was a tough decision to leave him out.

"I saw Nathan Bock play in the SANFL last weekend and I was really pleased with his form and his attitude," Craig said.

"Phil's been in good form and played some good football, but in the end I decided to go for Nathan Bock over Phil Davis.

"It goes down the chain and those other guys (Scott Stevens and Ben Rutten) are still in front of him, but Phil will come back and he'll be an outstanding player for our football club.

"He's disappointed and he wanted to get some clarity in the reasoning, which I would have as well as a player … but this won't be a setback for Phil Davis. He's an outstanding young man."