BRISBANE is closing on the re-signing of key defender Darcy Gardiner, which is set to take one of the last remaining restricted free agents off the market.

It's understood Gardiner has agreed to a long-term extension with the Lions, having attracted interest from a host of Victorian clubs throughout the season.

The Lions confirmed the new contract on Thursday afternoon.

Gardiner entered Brisbane's finals campaign as one of only three restricted free agents left unsigned, but is set to follow Sydney superstar Lance Franklin in securing his future at his current club.

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It will leave Collingwood's Jordan De Goey as the only unsigned restricted free agent. As revealed by AFL.com.au last week, the Magpies have tabled the star mid-forward a five-year offer with behavioural clauses but he also has interest from St Kilda.

Gardiner, a 193cm lockdown key defender, has enjoyed an impressive 154-game career with Brisbane and was an ever-present for the side throughout its most recent season and finals campaign.

The Lions are entering a crucial Continental Tyres AFL Trade Period, where the club is expected to land Western Bulldogs best and fairest Josh Dunkley and Hawthorn's free agent forward Jack Gunston.

Brisbane, which currently holds picks No.15, 33, 44 and 69, will also secure likely top draft choice Will Ashcroft as a father-son prospect, as well as talented Academy product and potential top-20 selection Jaspa Fletcher.