Essendon has been left with just one geniune ruckman due to the injuries to Tom Bellchambers and Jason Laycock.
Laycock has battled navicular problems since late last year but made his comeback with VFL affiliate the Bendigo Bombers the weekend before last.
"He's training and was playing with discomfort," Essendon coach Matthew Knights said.
"It's not ideal. He hasn't been able to get a run at it, which is frustrating because he would have been perfect to come in."
Youngster Patrick Ryder will be expected to carry Essendon's rucks in their absence.
"We're going to have to be a bit creative and share the workload. It's probably far to say Paddy is going to have to do the majority of the work, but we're going to have to find him support," Knights said.
"We'll have a chat about that this afternoon and try to come up with a plan that will give Paddy enough support and do our best to nullify Adelaide's strengths as well."
Essendon's ruck crisis has deepened, with Matthew Knights confirming that Jason Laycock could be ruled out for the season.