PORT Adelaide has suffered a triple blow ahead of Showdown 46, with co-captains Ollie Wines and Tom Jonas and veteran Brad Ebert ruled out of Saturday night's encounter with Adelaide at Adelaide Oval.

However, the club has confirmed veteran defender Matthew Broadbent will return for the Showdown, marking his first game since round 19, 2017.

SHOWDOWN PREVIEW Port Adelaide v Adelaide

Scans revealed Wines has a small fracture in his fibula after he pulled up sore after last Friday night's loss to Collingwood at Marvel Stadium.

Wines will miss at least a month, and the 24-year-old is expected to return shortly after the Power's mid-season bye in round 12.

Jonas will miss a third straight game with a calf injury, while Ebert hasn't recovered in time after suffering a concussion against the Magpies.

FULL INJURY LIST Who's ruled out and who's a test?

"It turns out Ollie has been running around with a broken ankle on the weekend, he's got a little fracture in his ankle, so he's going to miss a bit of footy," Jonas told The Advertiser.

"Ebo (Ebert) will also miss, concussion is a big deal these days and it should be, we've seen a couple of things over in the (US) and closer to him about the lasting impacts.

"He's got a couple of kids now to think about so he'd like to back in the docs and err on the side of caution if there is any risk."

Jonas said his recovery from his calf injury had been slower than expected.

"That sneaky calf, it's really got me," Jonas said.

"I sort of thought if I miss the North game (a fortnight ago) I'd be right for Collingwood, then I had a bit of a trot around last Thursday and pulled up sore from that straight away.

"Then I haven't really progressed over the weekend. I was going to run today but thought we'd hold it till Thursday or next week and see where it's at.

"It's one of those things, we might as well get it right and make sure we don't do any further damage."

Former captain Travis Boak could lead the Power once again with Wines and Jonas sidelined.