PROMISING Port Adelaide midfielder Joe Atley has ended speculation about a possible move to North Melbourne to play alongside his brother by signing a two-year extension with the Power.

Atley and mature-age rookie-listed defender Jarrod Lienert have inked new deals with the Power until the end of 2020.

Atley was the 32nd overall pick in the 2016 NAB AFL Draft, but didn't add to his three senior games this year, with a back injury limiting him to 10 appearances in the SANFL.

He's also behind several more experienced midfielders at the Power, leading to talk he could have requested a trade to the Kangaroos to join older sibling Shaun.

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"Unfortunately, Joe's 2018 season was significantly hampered through injury, but as our people would know, he has shown promise in both the SANFL and AFL competitions since being drafted to the club before the 2017 season," Port Adelaide general manager of football Chris Davies said.

"We're pleased he's chosen to stay and look forward to his body giving him the opportunity to continue to progress over the next two years."

Lienert, 24, made his debut in round 18 against Greater Western Sydney and held his spot in the side for the last five games.

"Jarrod had a breakout year in 2018, earning his AFL debut after some really consistent SANFL form," Davies said.

"His contract extension comes after showing real composure with the ball at AFL level, and we believe he will continue to develop after coming into the club as a mature age rookie."

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A new deal for veteran swingman Justin Westhoff appears to be a formality.

Jake Neade, Jack Trengove, Trent McKenzie and rookies Cameron Hewett, Peter Ladhams and Will Snelling are also unsigned.

Winger Jared Polec will join North Melbourne on a lucrative five-year deal during the trade period.

Contracted star Chad Wingard has attracted interest from the Western Bulldogs, St Kilda and Hawthorn, while experienced defenders Jack Hombsch, Jasper Pittard and Matthew Broadbent could be on the trade table.

Lindsay Thomas has retired, and Jimmy Toumpas and Emmanuel Irra have been delisted.