Fremantle skipper Nat Fyfe is set to miss up to five weeks with a hamstring injury, while ruckman Aaron Sandilands has been ruled out for three weeks.
Fyfe injured his right hamstring during last week's 55-point loss to Brisbane, and the club expects him to miss four or five weeks.
Sandilands injured his right calf during the warm-up, and has been ruled out of matches against Melbourne, Port Adelaide, and Essendon.
In better news for Fremantle, defender Alex Pearce made it through the match without suffering any further damage to his injured thumb.
Pearce underwent surgery on his broken thumb last month, and there were reports he re-injured it in his return game against Brisbane.
But Fremantle football operations manager Chris Bond dismissed those concerns.
"Obviously to play the game out against Adelaide when he broke the thumb was a great effort, and then to come back, there were no issues for him," Bond said.
"He's pulled up really well."
Premiership wingman Brad Hill also pulled up well in his first match back since injuring his knee in round two.
Hill tallied 25 disposals for WAFL side Peel Thunder, and appears certain to return to Fremantle's senior side for Saturday night's clash with Melbourne in Darwin.
The former Hawk had to play in the WAFL last week to serve his one-match AFL ban for his misdemeanour at a Perth night spot in May.
Hill also lost his spot in the club's leadership group over that incident.
The loss of Sandilands is set to open the door for Sean Darcy to make his senior return.
Darcy enjoyed a stunning start to his AFL career last season, but suffered a PCL injury to his left knee in April this year.
The 20-year-old has played in the past two WAFL games, racking up 12 disposals, 31 hit-outs and three goals for Peel Thunder last week.
Lyon was scathing of his team's insipid performance against the Lions and is demanding a far better display against the Demons.
Melbourne (8-6) have lost their past three matches and will need to beat the Dockers to keep their top-four hopes alive.