Josh Treacy during the round 21 match between Essendon and Fremantle at the MCG, August 4, 2024. Picture: Getty Images

FREMANTLE star Josh Treacy faces an uphill battle to face Greater Western Sydney in a crunch game on Saturday after missing Wednesday's main training, as he is carefully managed with a knee injury.

Coach Justin Longmuir declared the important key forward was "more unlikely than likely" to travel for the clash at Engie Stadium as ruckman Sean Darcy also pushes to return from knee soreness.

The coach said he remained hopeful of regaining Treacy but there would be a no-risk policy with the 22-year-old, who has proven to be arguably the Dockers' most important player in a standout 45-goal season.

"He's going to be touch and go and probably more unlikely than likely. It's improving, but we just can't take a risk on it, so there's a chance he'll miss another week," Longmuir said on Wednesday.

"He'll do minimal [training], so that's probably an indication of where he's at.

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"It's clearly a week-by-week injury. I thought he was a chance to get up last week, and so did the medicos. We were hoping he'd get up this week as well, but it probably hasn't improved as quickly as we need.

"We can't take any risk with him, so we just need to get it right."

Darcy trained lightly on Wednesday away from the main group, completing run throughs on the boundary after missing Saturday's loss against Geelong, which saw the Dockers use Pat Voss as Luke Jackson's ruck support.

Asked how Darcy was progressing, Longmuir said: "Better. He's in a good space. He hasn't done much since the game, so he'll do a bit more at training today and we'll try and get him back in and see how he goes."

Sean Darcy warms up before the round 22 match between Fremantle and Geelong at Optus Stadium on August 10, 2024. Picture: AFL Photos

With Darcy in doubt, back-up ruckman Liam Reidy is firming to make his debut after being left off the emergencies list last week and missing out in favour of veteran key forward Matt Taberner.

Longmuir said Reidy was prepared to play this week if needed after getting important WAFL minutes and racking up 54 hit-outs and 19 disposals.

The 24-year-old rucked with the stronger line-up during Wednesday's match simulation against Max Knobel, while Jackson played as a tall forward. 

"There's a lot that goes into that decision [not to play Reidy against Geelong]. We probably thought Sean was going to play, and to make your debut being the carryover emergency, whether that's the right thing for someone," Longmuir said.

"Plus, he needed to get minutes in case Sean didn't get up this week. If he had have missed on the weekend it would have been one game in five weeks, so match fitness becomes an issue.

"Then against Geelong, last year down in Geelong Luke played as the No.1 ruckman and did a really good job, so we probably leaned on that evidence."

With Darcy set to manage knee soreness through the rest of the season, Longmuir said a decision hadn't been made on whether the issue would require surgery at the end of the year and the goal was simply to get him through the campaign.

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On the Giants, Longmuir said his players were prepared for a multi-faceted challenge against one of the competition's in-form teams. The Dockers have an 0-3 record at Engie Stadium, losing their most recent clash at the venue to the Giants by 70 points in round 14, 2023. 

"They'll throw a lot of different things at us, and they work really hard. Their contest is good, they're moving the ball really well, and they defend their front half really well, which probably gets forgotten.

"They'll challenge us in all phases, but we're confident that if we play our best footy we can get the result.

"It’s a great challenge for us to go to Sydney again and somewhere we've never won and play a really good side. We’re excited about it."