OUT-OF-CONTRACT All Australians Paddy Ryder and Todd Goldstein are set to be the major players in this year's looming ruck merry-go-round.

Scott Lycett, Rory Lobb, Braydon Preuss, Tom Hickey and Jordan Roughead – now a key defender – switched clubs in the 2018 player movement period and more of the same is tipped to occur.

The situation is likened in AFL circles to the annual quarterback swap-a-thon that takes place in the NFL.

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Victorian clubs are also monitoring promising Dockers giant Sean Darcy, a Geelong Falcons product.

AFL.com.au understands Port Adelaide is willing to offer Ryder just a one-year deal at this stage, whereas he may be able to secure a multi-season contract elsewhere.

Todd Goldstein and Sean Darcy in battle in round one. Picture: AFL Photos

A rival offer for the 31-year-old West Australian could include a games trigger.

Goldstein, who turns 31 at the start of July, is an unrestricted free agent and his future is somewhat in limbo after former coach Brad Scott parted ways with North Melbourne.

Significant list decisions won't be made at the rebuilding Kangaroos until Scott's replacement is hired post-season.

St Kilda, which missed out on Lycett last year, is believed to have shown interest in both Ryder and Goldstein despite Rowan Marshall's emergence.

Fellow Saints ruckmen Billy Longer and Lewis Pierce have each played once at senior level this year, both times when Marshall wasn't in the team.

Essendon, Gold Coast, Richmond and the Western Bulldogs could also look to bolster their ruck division.

Goldstein is one of North's highest-paid players and has returned to somewhere near his best form in the past 18 months, after a lean 2017 campaign that saw him dropped to the VFL.

Recycled former Bulldog Tom Campbell and developing second-year big man Tristan Xerri are North's chief ruck back-ups since Preuss left for the Demons.

Ryder's situation is different to Goldstein's, because a trade would need to be negotiated.

Paddy Ryder in action for Port in China. Picture: AFL Photos

The 2017 All Australian has a history of Achilles problems, but has played all 11 matches this season and proven a fairly durable player throughout his career.

However, Lycett's arrival from the Eagles provided Port Adelaide with another genuine No.1 big man, and the SANFL form of 202cm ruck-forward Peter Ladhams has created an interesting situation.

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Ladhams, who made his AFL debut in round 10 as cover for an injured Lycett, is averaging 22.6 disposals, six clearances and 25 hit-outs at state-league level this year.

The Power also has 200cm Billy Frampton, who is being used as a key forward and back-up ruckman, and highly rated but untried 203cm teenager Sam Hayes.

A season-ending knee injury ruined Hayes' rookie campaign and he is currently recovering from glandular fever.

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Darcy, who turns 21 next week, is contracted at Fremantle until 2022, but it was noted that he spent five weeks in the WAFL, even in Aaron Sandilands' absence, before an ankle injury sidelined him.

There is a ruck logjam at the Dockers, with retirement-bound Sandilands, Darcy, Lobb, Scott Jones and Lloyd Meek all fighting for spots.

Behind Goldstein and Ryder are a bunch of lower-profile options that could come into play for teams that miss out on the star duo.

Among those potentially seeking greater opportunity are Hawthorn's Marc Pittonet and Swan Darcy Cameron, whose situation became more clouded with Michael Knoll's mid-season drafting.

Cats pair Wylie Buzza and Zac Smith, like Pittonet and Cameron, are out of contract at season's end and on a list stacked with talls, including Rhys Stanley, Darcy Fort and Ryan Abbott.