FREMANTLE'S ruck stocks are set to be tested, with big men Jonathon Griffin and Zac Clarke both experiencing interrupted pre-seasons. 

Achilles soreness has restricted Griffin to training away from the main group, while Clarke has had knee surgery.

The Fremantle playing group has been given two weeks away from the club over the Christmas and New Year period, but Griffin told the club's website he still has some work to do as he tries to overcome his Achilles complaint. 

"I should be back in the main group just after Christmas, I’m just nursing it along at the moment and it’s nothing serious," Griffin said. 

"I just really value being out there and doing as much pre-season as I can. I know how well that sets me up for 2017. 

"At the moment it’s just putting all of my energy into getting my body right and healthy, and everything else will just take care of itself." 

Clarke on the other hand, will need more time as he recovers from yet another operation on his knee. 

The 26-year-old has had ongoing knee problems and injured a ligament in his patella during the pre-season. 

He has since had surgery to repair the issue but is still at least a month away from returning to the track.

Griffin and Clarke shouldered the majority of the ruck load last season with No.1 big man Aaron Sandilands missing most of 2016 with broken ribs.