BULLOCKING young Fremantle ruckman Sean Darcy was annoyed to be rested for Saturday night's clash against Gold Coast and has vowed to improve his skinfolds to better cope with the demands of playing AFL.

Darcy has been a huge positive for the Dockers this year, stepping up in Aaron Sandilands' absence and playing the past six games.

The 19-year-old has averaged 33 hit-outs and nearly 12 disposals, and many observers have been bemused he hasn't received a NAB AFL Rising Star nomination.

After a hefty workload, Darcy showed signs of fatigue late in last round's loss to GWS and, despite his protests, has been given the weekend off.

"I tried to challenge it. I tried to say 'oh, are you sure?' but they didn't really listen to me. They took their way, so that was a bit annoying, but anyway … " Darcy said.

"I've just got to listen to them and do what they say.

"My body is a bit sore. The intensity, it's a bit quicker.

"I did drop-off a bit (against GWS), I was a bit disappointed. I'll have this week off and hopefully be better by next week."

Darcy is an impressive runner for a 201cm and 111kg teenager, but after getting a taste of the big time he knows his conditioning can improve.

"I want to come back (next year) as well as I possibly can, so I'm pretty determined to do that," Darcy said.

"My conditioning coach has just said we just want to get our skinfolds down.

"I can keep the weight on if I can run alright."

Darcy has shown there is ruck hope after Sandilands for the Dockers, although he is thrilled his mentor will play on next season and believes they can play in the same team.

In their only match together in round 15, Sandilands lasted less than a quarter before suffering a season-ending hamstring tendon tear.

Fremantle is searching for marking targets in attack and Darcy, taken with pick 38 in last year's NAB AFL Draft, hopes to help fill the void by improving his forward craft.

"If I get another pre-season in my belt and hopefully learn my craft up forward I can see that (playing with Sandilands) happening," he said.

"He sits down every week with me and goes over film and just gives me advice about this is what I would do, this is what he would do.

"Even the last few weeks he's been telling me 'this is what I saw', he's been unreal with me."