HAWTHORN expects defender Changkuoth Jiath's season is likely over, with the exciting Hawk to undergo scans after suffering a knee injury against Fremantle on Saturday.

Jiath, who landed awkwardly after flying for a mark late in the third quarter, has a suspected posterior cruciate ligament injury and coach Alastair Clarkson said the club would take a conservative approach with the important 22-year-old.

"'CJ' has got some form of PCL injury, so he is unlikely to play for some time," Clarkson said after the Hawks' 62-point loss to Fremantle at University of Tasmania Stadium. 

"Usually our way of treating these is to put them in some sort of brace and they come up over the next little while.

"We'll probably take a conservative approach with him and with only six weeks it will probably mean that it would be doubtful he gets back for this year."

The Hawks' defence was hit hard on Saturday, with Blake Hardwick withdrawn pre-game with a hamstring injury and Jack Scrimshaw suffering a head knock after also experiencing a migraine.

The Hawks sent impressive youngster Lachie Bramble to defence, where he was a solid contributor, but Clarkson said the team could not match Fremantle's sharp ball movement.  

"A lot of our rebound from the back-end is all on our injury list at the moment," Clarkson said.

"Just getting some flow and some bounce in our game, we just couldn't do it anywhere near as well as Fremantle."

Fremantle coach Justin Longmuir praised the evenness of his team's performance after a deep midfield got the job done in captain Nat Fyfe's 200th game.

The Dockers used Fyfe as inspiration pre-game, with Longmuir challenging his players to mirror the captain's on-field traits.

"I wonder whether players can actually try harder than they would normally, but we just spoke about a few behaviours that Fyfey exhibits that we could carry out," the coach said.

"That was largely around his competitiveness and his calmness. He's never flustered out on the oval and we thought if we could be on task and remain in the moment as much as he does as a team it would hold us in good stead.

"I was really rapt for the way he performed and the way we performed in a big milestone."

The Dockers moved into seventh spot on the ladder on Saturday night, but Longmuir said the young team could not get too far ahead of itself.

The coach said he could not be more pleased with breakout ruckman Sean Darcy's application this season after another star performance with 25 disposals, six contested marks and five clearances.  

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He said the 23-year-old's challenge was to maintain his form now over an extended period after joining the AFL's elite bracket of big men. 

"He's done it for the last probably 14-15 weeks," Longmuir said.

"He's got a real hunger about improving his game and he's got a real competitiveness in his game on and off the field.

"Those things will hold him in good stead.

"The challenge now is he keeps backing it up week after week."