PORT Adelaide has dropped club leader Tom Jonas and put fellow backman Alipate Carlile out for a spell.

Power coach Ken Hinkley says the duo are among "four or five" changes for Thursday night's match against Collingwood at Adelaide Oval.

Hinkley says Port's predicament – 12th spot with a 5-8 record – demands action at the selection table.

"We have to make some more changes," Hinkley said.

"Tommy Jonas won't play. He's part of our leadership group and been a significant member of our football club.

"I trust Tommy with everything I have got. Unfortunately his form has not been well.

"Bobby Carlile has been struggling physically, he's not going to play.

"There will be other changes that we will make, there will be four or five, and we have to do that to try and create some form."

Hinkley said the defensive posts of Jonas and Carlile would be filled by Jackson Trengove, who is returning from injury, and Tom Clurey, who has played four senior games.

"There is great upside in the disappointment of other players, we get a chance to see some other boys continue to improve," he said.

"But it's not one player. It's the collective. The whole 22 are going to be needed."

Asked if Port's season was on the line against the Magpies, Hinkley replied: "It has been at that stage for a while.

"We are challenged each week and we have to continue to look to respond.

"And that is our challenge again on Thursday night. Look to respond and get some of our football back to where we need it to be."