FREMANTLE recruit Harley Bennell won't be available to make his Dockers debut until the second half of the season as he is set to undertake an eight-to-10-week program to rehabilitate his injured calf.

Bennell re-injured his calf playing in round one of the WAFL, just a week prior to the start of the AFL season.

Dockers coach Ross Lyon said last week that the club had sought specialist advice on Bennell's calf issues from AIS head of physical therapies, Craig Purdam.  

Freo confirmed on Tuesday that Bennell would be out for eight-to-10 weeks in an effort to fix the calf issues for the long term.

The club also said that ruckman Aaron Sandilands would miss six weeks following the severe rib and lung injury he suffered against West Coast on Saturday night. 

Sandilands is still in hospital after needing surgery on Sunday to fix multiple fractures and re-inflate his punctured lung.   

Skipper David Mundy will miss this week's crucial clash with North Melbourne with a calf problem. He was ruled out of last week's Western Derby last Friday after suffering the injury at training on Thursday. 

The Dockers are hopeful Mundy will be right for the round five clash with Carlton at Domain Stadium.