Fremantle have been on a learning curve with Harley Bennell after pushing him "beyond what he needed to be pushed" during his calf rehabilitation, coach Ross Lyon says.

Bennell is in the last stages of his preparation to make a long-awaited return to football, potentially as soon as next weekend at Peel. 

It has been a torturous road marred by multiple setbacks and controversial off-field incidents for the 24-year-old since his last game for the Thunder way back in March last year. 

Bennell flew to Germany for specialist treatment in December and was aiming to play in the early rounds this season.

But Lyon admitted the Fremantle Dockers had erred by trying to make him bulletproof before his comeback, with the ex-Sun suffering more calf issues at training.

"Really in reality, we probably pushed Harley beyond what he needed to be pushed - trying to create something like Superman really," Lyon said. 

"In theory, he probably could have been playing. But we're learning some lessons on how to handle Harley."

"Really simply he was 40 per cent above our cohort average on leg strength, on calf strength, and coming to the club he was probably the weakest.

"So that gives you context of how hard he worked and how hard we pushed him.

"But in hindsight, could we have backed it off earlier, did we need to take him to that level? But we were trying to build something really strong and sustainable.

"The intent and the work rate was amazing." 


Harley Bennell and Nat Fyfe in action at training on Wednesday

Lyon said Bennell needed to hit high levels and volumes of speed before he would be ticked-off to play "because that's the risk, because he's so quick".

In more promising news for Freo, superstar skipper Nat Fyfe and giant ruckman Aaron Sandilands are "looking likely" to return against St Kilda on Sunday.

Sandilands has missed the past four losses due to hamstring tendon inflammation, while Fyfe has been battling a bruised sternum and was withdrawn from last Sunday's gutsy defeat at Geelong.

"He pushed to play last week. He trained. But he wasn't playing in the manner that we desired, and he desired," Lyon said.

"He's really courageous – we know that. I've seen him play with a broken leg.

"Sometimes you've got to save them from themselves and make a hard decision.

"In the end, the doctor ruled him out, and said 'you'll benefit greatly from this'. So he's really up and about and keen to play."

The Freo Dockers have struggled to hit the scoreboard this year – ranking 17th for points – and with Cam McCarthy and Shane Kersten both battling to have an impact recently, Fyfe might be pushed forward.

"We know he's an absolute strength down there in the air and a competitive beast," Lyon said.

"Just having him around will make Kersten, McCarthy and everyone walk a bit taller."

Lyon also hinted that powerful young ruckman Sean Darcy might have to make way if Sandilands returned, despite an impressive debut of 40 hit-outs and 14 disposals against the Cats.

"We've been down that path before (with two ruckmen), but we've liked the mobility of one," the coach said.

Freo could also consider bringing back Ed Langdon (knee) and Brady Grey (hamstring) against St Kilda on Sunday, with both players named as tests this week.