Oscar Allen leads West Coast out against Port Adelaide in round one, 2024. Picture: AFL Photos

WEST Coast co-captain Oscar Allen is expected to avoid surgery for a right knee injury as the Eagles continue to investigate the star forward's bone stress issue before settling on a timeline for his return to play.

Allen reported swelling in his right knee following the club's round-one loss to Port Adelaide, with subsequent scans late on Tuesday revealing the stress-related setback.

The Eagles were not in a position late on Wednesday to confirm a timeline for his return, but sources close to the 25-year-old were confident the injury would be treated with a period of rest rather than surgery.

West Coast has endured extensive injury issues for the past two seasons, and Allen's stress-related setback has raised concerns that the club is set for another difficult campaign in the medical room and on-field.

Chief executive Don Pyke on Wednesday called for calm on the Eagles' injury front, however, telling News Corp that Allen's injury was "not related to what has gone on in the past".

Allen is almost certainly the club's most important player after returning in 2023 from a stress fracture in his foot and kicking 53 goals, earning elevation to the co-captaincy ahead of this season and proving himself as an influential leader over the summer.

He underwent precautionary scans on his knee following the Eagles' match simulation against Fremantle and was then rested for the AAMI Community Series match against Adelaide. He wore strapping on his right knee against the Power on Sunday.

Oscar Allen leads West Coast out against Port Adelaide in round one, 2024. Picture: AFL Photos

Allen's absence has now opened an opportunity for young forward Ryan Maric, who announced a contract extension on Wednesday through to the end of 2026, or 20-year-old Jack Williams, who also shapes as a support ruck option.

The Eagles revised their injury prevention protocols at the end of last season and secured new high performance boss Mathew Inness from the Western Bulldogs.

The club has had a process for reviewing the hardness of its training base at Mineral Resources Park, testing the two grounds weekly to ensure they sit within a safe range every week.

Allen is one of nine players on the Eagles' injury list, with ruckman Matt Flynn (knee) and draftee Archer Reid (knee) facing at least seven and five weeks on the sidelines respectively.

Young midfielder/forward Elijah Hewett is not recovering as quickly as hoped from sesamoiditis in his feet after visiting a Melbourne-based specialist to kick-start his rehabilitation program.

Defender Harry Edwards (finger), midfielder Jai Culley (knee), and premiership pair Dom Sheed (foot) and Liam Ryan (hamstring) all are set to return inside the next month. Rhett Bazzo (groin) will start running in the next week.