Eagles co-captain Allen sidelined with knee injury

West Coast have been dealt a horror blow to the start of their AFL campaign, with co-captain and spearhead Oscar Allen sidelined with bone stress in his right knee.

Goalkicker Allen had scans on Tuesday after his knee swelled up in the wake of Sunday's 50-point loss to Port Adelaide.

The Eagles put out a statement late on Tuesday night saying Allen had not reported any soreness before, during or after the game.

They did not put a time-frame on Allen's return.

"The club will continue to assess Allen's knee and provide an update in coming days when a return-to-play time-frame becomes clearer," the Eagles said in a statement.

The Seven Network reported the key forward could be sidelined for six to eight weeks.

West Coast Eagles AFL player Ryan Maric (centre).
Allen's likely replacement Ryan Maric (centre) has scored nine goals in 10 games for West Coast. (Joel Carrett/AAP PHOTOS)

Ryan Maric, who looms as Allen's replacement for Sunday's home clash with Greater Western Sydney, signed a two-year contract extension on Wednesday - tying him to the club until the end of 2026.

Maric has kicked nine goals in 10 games since being selected with pick No.1 in last year's mid-season draft.

But the 19-year-old has big shoes to fill, with Allen's absence a hammer blow to West Coast's chances this year.

Allen had appeared set for a big campaign after booting 53 goals last year and taking on the co-captaincy.

On the eve of the season, the 25-year-old spoke about his goals for 2024.

"I want to become a more well-rounded player," he said.

"It was nice on a personal note to be able to play consistently last year, coming off 2022 and not being able to get out there (due to a foot injury).

"So last year my main goal was to play every week. And now I've ticked that, my goal is to play every week at a higher level more consistently,"

Allen's absence comes as last season's wooden-spooners prepare to face a rampant GWS.

Fellow senior Eagles Liam Ryan (hamstring) and Dom Sheed (foot) are still at least three weeks away from a return.

"Liam and Dom are both progressing well. We expect to see them in pretty much full training this week," high-performance manager Mat Inness told the club's website.

"Now it's just a matter of building up their loads so hopefully we'll see them return to play in the next three to four weeks."

No timeline has been set for Elijah Hewett's return as the young midfielder's recovery from an overuse injury to both of his feet drags on.