Campbell Heath, Daniel Stewart and Sam Colquhoun have been omitted from the team.
Dom Cassisi, Matthew Lobbe and Paul Stewart come back into the side in their place.
Senior coach Ken Hinkley said this week's selection was based on performance.
“(The decision is) predominantly based on their form,” Hinkley told portadelaidefc.com.au.
“We went with the decision last week to see if we could go one with ruckman and Daniel Stewart came in to play as a ruck/forward, but we didn’t think we got enough out of that decision so we’ve gone back to having the second ruck in the side,” he explained.
Hinkley says Lobbe needs to work on impacting the whole match, rather than performing well in short periods.
“He’s just got to be more influential in the game for longer periods of time,” said Hinkley.
“We’ve had ‘Lobbes’ play previously and we’ve loved what he’s done for parts of the game, but we just need him to be for an extended period of time.”
Heath’s omission comes after he was substituted midway through last weekend’s loss to Richmond.
It gives previously injured veteran Dom Cassisi the opportunity to come back into the Power’s 22.
“It gives us an opportunity for Dom to come back into the side,” said Hinkley.
“Campbell was obviously subbed last week and his form hasn’t been quite where we’d like it to be, and he’s paid the price for Dom to come back in and give us something in that (defensive) area.”
Colquhoun comes out of the side after playing his debut game last week.
He along with Tom Logan and Cameron Hitchcock are the named emergencies.
Sunday’s match against Carlton will be a crucial fixture for Port, with a victory capable of solidifying the club’s place in the top four.
Hinkley expects a massive challenge despite the Blues coming off a short break following their loss to St Kilda on Monday night.
“A Mick Malthouse-coached team is going to be desperate to atone for last week’s loss,” said Hinkley.
“We know they’ve got a couple of players out but the quality of players they could bring in – guys like Jarrad Waite, Bryce Gibbs – is very good.”
“We’ve got a challenge in front of us.”
portadelaidefc.com.au will have live coverage of the Power’s Round 8 match from 12:40pm (CST) on Sunday 19 May and the final squad first on Friday afternoon.
Port Adelaide Round 8 final team v Carlton
FB: Lewis Stevenson, Alipate Carlile, Cameron O'Shea
HB: Dom Cassisi, Tom Jonas, Andrew Moore
C: Kane Cornes, Travis Boak, Brad Ebert
HF: Matthew Broadbent, Justin Westhoff, Angus Monfries
FF: Robbie Gray, Jay Schulz, Chad Wingard
Foll: Jarrad Redden, Hamish Hartlett, Oliver Wines
Int from: Jake Neade, Matthew Lobbe, Kane Mitchell, Paul Stewart
Emg: Cameron Hitchcock, Tom Logan, Sam Colquhoun
In: Dom Cassisi, Matthew Lobbe, Paul Stewart
Out: Campbell Heath, Daniel Stewart, Sam Colquhoun (omitted)
