FREMANTLE has suffered another blow to its defensive stocks with Joel Hamling to miss the start of the season with a serious ankle injury.

The premiership defender suffered significant damage to the ligaments in his left ankle after landing awkwardly at training on Monday.

The Dockers haven't put a timeframe on his recovery, but he looks set to miss at least the first few rounds of the season.

"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," general manager of football 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 defender Alex Pearce has missed the majority of pre-season after undergoing surgery on his left ankle in December.

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.