Fremantle will start the AFL season without their best two defenders with Joel Hamling the latest star to be struck by injury.

Hamling is set for a lengthy stint on the sidelines after suffering serious ligament damage in his left ankle at training on Monday.

No exact timeline has been set for the 26-year-old’s return but the Dockers have already ruled him out for the start of the home-and-away campaign.

“Joel landed heavily on his left ankle after contesting a mark at training on Monday and was sent for scans, which confirmed the nature of the injury,” Fremantle football operations manager Peter Bell said.

“He will be further assessed by a specialist, after which we will have a more accurate estimate of the recovery time Joel’s injury will require.”

Fellow key backman Alex Pearce will also miss the start of the season after undergoing more surgery in December on the left ankle he fractured in round 11 last season.

The loss of Hamling and Pearce is a huge blow to the Dockers under new coach Justin Longmuir.

Star forward Jesse Hogan also appears set to miss the start of the season while he continues his recovery from a serious navicular foot injury that required surgery.

Hogan is currently on indefinite leave so he can focus on his mental health and he faces an uphill battle to prove he is both physically and mentally ready for round one.

It’s also unclear when midfielder David Mundy will return.

Mundy suffered a fibular fracture above his left ankle in a freak accident while riding an exercise bike with his children.