Giants tagger Matt de Boer. Picture: AFL Photos

GREATER Western Sydney has lost Matt de Boer to a back injury on the eve of its must-win clash with St Kilda, with the important lockdown midfielder replaced in the selected side by Isaac Cumming.

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Having missed three matches earlier this season due to a hamstring injury, de Boer's late omission means the Giants go into the clash at the Gabba having made three changes as they look to keep their fading finals hopes alive.

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Captain Stephen Coniglio had already been named to return, having been dumped from the team for last week's loss to Melbourne, while young forward Jake Riccardi is also included in place of Adam Kennedy and Harry Himmelberg respectively.

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The Saints are unchanged from the team named on Thursday night, which included experienced duo Dan Hannebery and Jake Carlisle replacing the injured Zak Jones and the omitted Nick Hind.

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St Kilda will secure a return to finals with victory, while GWS will need to win and hope that results involving either the Western Bulldogs or Melbourne go its way later in the weekend to have any chance of progressing this season.