GREATER Western Sydney has a battle on its hands to retain out-of-contract key defender Josh Bruce with a growing number of opposition clubs circling the 21-year-old from Canberra.

AFL.com.au understands St Kilda leads the chase for Bruce, with Carlton, the Brisbane Lions and North Melbourne among other interested clubs.

However, the Giants are fighting hard to keep the 196cm defender, who was recruited from Eastlake in 2011 as a NSW-ACT zone selection, having recently offered him an attractive contract extension.

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Bruce played 11 of the Giants' final 17 games in his second AFL season this year, showcasing the freakish athleticism that industry sources say has captured the attention of opposition recruiters.

Bruce is understood to be happy at the Giants, but is presumably mindful that GWS added three highly touted key defenders to its list in last year's national draft: Lachie Plowman (pick No. 3), Kristian Jaksch (12) and Aidan Corr (14).

Fellow key backmen Phil Davis, 23 last month, and Tim Mohr, 25 next month, also look set to be long-term fixtures in the Giants' defence.
Bruce got a taste of senior football in his debut season, 2012, playing three games, but took significant strides this season.

Twitter: @AFL_Nick.