AARON Sandilands' calf injury has opened the door for his Fremantle protégé Sean Darcy to return for arguably the AFL's toughest ruck challenge against Melbourne giant Max Gawn in Darwin on Saturday night. 

Darcy's encouraging progress was halted by a PCL injury in April, but the bullocking 201cm youngster will partner Michael Apeness, while speedster Bradley Hill is also back for his brother Stephen's 200th game.

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Dockers coach Ross Lyon was bullish about Sandilands' future after his calf setback and still hopes the 35-year-old and Darcy will play together in 2018.

But, for now, Lyon was excited to see the 20-year-old back to build on his eight appearances last season, after getting through two WAFL games.

"He's had a rough run and he's part of our future, and he's a big, powerful ruckman," Lyon said.

"It (selection) was hard, Scott Jones has been in good form, but he spends a bit more time in the ruck.

"It would be nice if he (Darcy) had a couple more (games) to build, but the reality of the situation is he needs to play."

Darcy and Apeness have only 19 games' experience between them but Lyon was confident the big men could compete against the 2016 All Australian ruckman, who leads the League in hit-outs (47.1 per match).

Gawn powers the Demons' engine room, and Melbourne is ranked No.1 for contested possesions and third for clearances, while Freo is 17th and 11th respectively.  

"It's certainly a challenge, but when I look in their eyes they're both (Apeness and Darcy) fierce competitors," Lyon said.

"They'll win their fair share and if you lose a few, as long as you're giving your maximum effort.

"Max Gawn wasn't always the player he was and he publicly talks about his story, about how he had to learn application and learn that craft and then took a number of years to become a top-flight (ruckman).

"That's the part of the story we recognise for everyone, it takes time and effort and our guys are on that path."

The Dockers (6-8) suffered a disappointing 55-point loss to Brisbane last round, which all-but ended their slim finals chances, and are expecting a ferocious Dees (8-6) outfit coming off three-straight losses.

St Kilda stretched the Demons with speed at the MCG last round and Hill's return at TIO Stadium will be important, with the Doig medallist replacing superstar Nat Fyfe (hamstring) after one game back from a knee injury at Peel last Saturday.

"It's a big ground and you need to run," Lyon said. 

"He'll come in and disrupt the defence by his line-breaking run, so that's critical, and it's nice synergy that it's Stephen's 200th."

Lyon praised the elder Hill for his outstanding career, which has included a hat-trick of Doig Medal podium finishes since he was drafted via pick No.3 overall in 2008.

"He's got great values as a footballer, he trains hard, he competes, he's a complete team player, he's very coachable and he's very close to his family," Lyon said.

"I still think the best is in front of Stephen."

Lyon said Harley Bennell was continuing to progress incrementally and would line-up for his seventh WAFL game on Friday night against Subiaco.

The injury-plagued ex-Sun had 21 touches, nine clearances and a goal last weekend, prompting speculation he could be back to face the Demons or next round against Port Adelaide.

"I'm not sure where the progression is at, but I think he might have a little bit more in front of him," Lyon said.