Subiaco suffered a significant blow on the eve of their vital match against Peel when rangy on-baller Jarrad Kayler-Thomson was ruled out for the rest of the season.
Kayler-Thomson will require surgery on the right shoulder he dislocated against East Fremantle last week.
The left-footer has an injury known as a SLAP tear - superior labrum from anterior to posterior - which will require arthroscopic surgery and can take up to four months to heal.
His absence today will leave the third-placed Lions vulnerable against a Peel team that dominated Perth last week.
Matt de Boer will play his first WAFL match in more than three years when he returns for the Thunder after overcoming a knee problem that forced him out of the Fremantle team a month ago.
Peel have named another 10 Dockers and could also regain Anthony Morabito, Kepler Bradley and Tom Sheridan who were listed as emergencies for the western derby.
Peel have only beaten Subiaco six times in 43 meetings but have won two of their past three visits to Medibank Stadium.
Coach Cam Shepherd was pleased with the team's development in recent weeks.
"We are playing pretty good footy but concentration lapses have hurt us," he said. "We just have to keep working hard to be positive and competitive."
Subiaco will regain lively forward Shane Yarran, who missed the loss to East Fremantle after he was concussed at training.
Yarran has kicked 21 goals this season to prove a valuable foil to spearhead Matt Boland and flanker Rhys Waters.