Fremantle's Heath Chapman grimaces in pain after hurting his shoulder against West Coast. Picture: AFL Photos

FREMANTLE'S injury woes have gone from bad to worse, with young duo Sam Sturt and Heath Chapman ruled out for the rest of the season.

Chapman dislocated his shoulder in Sunday's Western Derby loss to West Coast and will need to undergo shoulder stabilisation surgery.

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Sturt, who missed most of last season with a serious ankle injury, underwent surgery on Thursday after injuring his knee in the WAFL last week.

"Sam's done some damage to his meniscus in his knee," Fremantle football operations manager Peter Bell said.

"He's had a terrible run of luck with injury, he's got a lot of talent. We're fully behind Sam and we look forward to him also rejoining us healthy for pre-season."

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Defender Ethan Hughes (shoulder) and forward Bailey Banfield (ankle) are also set for extended stints on the sidelines.

"Ethan has a fracture in his scapula, which was a really tough contact in the derby," Bell said.

"At the moment we're just assessing the requirement for surgery around the potential for some nerve damage sustained in the injury.

"At the moment the signs are good, and we would manage that injury conservatively, but we just want to monitor that situation with the nerve.

"Bailey's a little bit different in that the specialist would like to wait another week or so to just see how that injury settles to determine whether there is the usual syndesmosis tightrope surgery, or we take a more conservative route and just recondition that injury without the need for surgery.

"We'll know a bit more in about a week's time."

Fremantle's injury list was already extensive, with key players such as Alex Pearce, Joel Hamling, Stephen Hill, Luke Ryan, Adam Cerra and Hayden Young all sidelined.

Fremantle will be back in action on Sunday when it takes on Brisbane at the Gabba.