The Dockers were left reeling when key backman Brennan Cox, fellow defender Hayden Young (ankle) and forward Michael Frederick (soreness) were all ruled out of Saturday's crunch clash with Collingwood at the MCG.
Young will miss between one to three weeks, while the Dockers are still determining a timeline for Cox.
Fremantle were dealt a further blow on Tuesday night when star midfielder Caleb Serong failed to overturn his one-match ban at the AFL Tribunal for a dangerous tackle.
Last week's sub Karl Worner (calf) has also been ruled out.
It means Fremantle will make at least five changes to their 23-man squad that went down to Carlton by 53 points last week.
Hamling, who won a premiership with the Western Bulldogs in 2016, is the feel-good story after being named for a long-awaited return.
The 30-year-old has played just two AFL games since suffering a serious ankle injury in February, 2020.
Hamling has returned to full fitness this year but with Alex Pearce, Cox and Luke Ryan marshalling the backline, he has been unable to force his way into the senior side until now.
"I'm stoked for him," Fremantle coach Justin Longmuir said.
"The work to get over his injury and rehab, get back to somewhere near his best physically, and to be able to go out there and deal with the frustration of not playing AFL and playing in the WAFL (is admirable).
"It's been a long road. He's deserving of an opportunity.
"I've been really proud of the way he's helped Josh Draper and Hugh (Davies) along to develop their careers while he's been at Peel.
"His game last week against Subi was really strong and his last month has been really strong.
"I'm proud of his journey, and he's got to go out there and play his role and he'll help that back six compete really hard."
Cox will also miss next week's clash with Sydney, meaning Hamling is a strong chance to play at least two consecutive games at the top level.Â
Mason Cox is set to be thrust back into Collingwood's lead ruck role for Saturday's clash after Darcy Cameron was ruled out with a back injury.
The Magpies will make at least three changes, welcoming back important trio Steele Sidebottom (knee), Brayden Maynard (shoulder) and Dan McStay (finger) from injuries.
Will Hoskin-Elliott has been ruled out with a broken hand.
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