GREATER Western Sydney forward Matt de Boer has been a late withdrawal from Saturday night's clash with Adelaide in Canberra with a hamstring injury.

Lachie Keeffe has come into the Giants' 22 for his fifth game of the season and will help cover the loss of ruckman Dawson Simpson (ankle), who is unlikely to play again this year.

The loss of former Docker de Boer is a blow for the Giants, with the 28-year-old averaging 20 possessions and four tackles in his 13 games this season playing across half forward.

His absence means the home side will rely on the returning Ryan Griffen, plus draftees Zac Langdon and Brent Daniels, to do the grunt work at ground level inside 50 against the Crows.

Adelaide goes into the must-win match unchanged.

The Crows currently sit outside the top eight and realistically must win all three of their remaining games to make the finals.