WEST Coast premiership forward Steven Armstrong will miss Friday night's showdown with St Kilda at Telstra Dome and could be sidelined until the finals after injuring his knee in Saturday night's 31-point victory over wooden spooner-in-waiting Richmond.

Armstrong, collected heavily by Tiger Jake King in the second quarter, strained a medial ligament later in the match and did not join his teammates at their recovery session yesterday morning. The club is hopeful Armstrong's setback is not serious.

And there are fears dependable tall utility player Jaymie Graham could have played his last AFL match for the season after tearing the medial ligament in his left knee for the second time this year in South Fremantle's loss to Swan Districts.

But West Coast is likely to be boosted by the return of premiership quartet Chris Judd (groin), Ben Cousins (hamstring), Beau Waters (finger) and Daniel Chick (larynx) for the clash with St Kilda, knowing full well that victories against the Saints and Essendon in round 22 will virtually assure the Eagles of second spot and two home finals.

West Coast is hopeful Brent Staker's report for striking Adam Pattison will be withdrawn, while Mark Seaby's heavy bump on Kane Johnson in the second half did not even draw a 50-metre penalty, suggesting a penalty from the match review panel is unlikely.

Seaby's availability takes on greater importance for West Coast on the eve of the finals because of Graham's continued wretched luck.

The 24-year-old missed a month earlier in the season with a medial problem and was playing his first game in six weeks on Friday night after overcoming a torn calf muscle.

Eagles football manager Steve Woodhouse said Graham, the obvious back-up for Dean Cox or Mark Seaby,would have scans today to determine the extent of the injury.

Graham has not been seen in an Eagles jumper since the round-14 loss to the Brisbane Lions and has been restricted to five matches for the season.

WEST AUSTRALIAN