Fremantle has been dealt a blow in its attempt to push for a top eight spot, with ruckman Aaron Sandilands set to miss the rest of the season.

Sandilands was returning from a four week lay-off due to a hamstring injury against St Kilda at Domain Stadium on Sunday.

However, the 34-year-old re-injured his hamstring in the first quarter of the match.

Dockers coach Ross Lyon confirmed post-match the side's star ruckman will not play again this season.

"It’s a significant injury and it’s season ending," Lyon said after the Dockers' nine point loss to the Saints.

More to come.