The Eagles need to replace injured premiership skipper Shannon Hurn and have opted for Witherden over young defender Luke Foley because of the former Lion's experience going into a crunch game.
West Coast coach Adam Simpson expected an under-pressure Collingwood would travel west with similar motivation to last year's elimination final, when they prevailed with their backs to the wall.
"There's no illusions about what's happening this weekend. It's game on," Simpson said.
