WEST Coast's raw forward line could be robbed of even more experience with star spearhead Josh Kennedy under an injury cloud for Thursday night's clash against Essendon.

The Eagles sorely missed in-form forward Jack Darling (ankle) in a hard-fought 15-point loss to Sydney at the SCG, with a youthful attack failing to capitalise on 63 inside 50s.

West Coast booted only 7.15 against the Swans – the club's lowest score for the season – as Sydney snapped the visitors' 10-game winning streak.

Kennedy kicked two majors but limped through the fourth quarter after receiving treatment in the rooms, and coach Adam Simpson revealed the dual Coleman medallist is no certainty to line up against the Bombers. 

"He got a knock on the knee. Structurally, it's all good. It's just how he pulls up and can we get him up for training tomorrow?" Simpson told Channel Seven.

"We'll give him every chance to play. We'll see how he pulls up. He's a bit sore, but there's no structural damage, which is a great thing for us."

Kennedy, Darling and full-back Tom Barrass (back) were absent from training on Monday, although Barrass completed some individual work before the main session got underway at Subiaco Oval.

If Kennedy is ruled out, debutant Jarrod Brander would be more likely to hold his spot after gathering only five touches against the Swans.

But the rangy 19-year-old wasn't the only Eagles forward with limited impact at the SCG.

Returning Liam Ryan (12 disposals, one goal), plus regular forwards Willie Rioli (seven disposals), Jake Waterman (10, one goal) and Jamie Cripps (14) combined for only two majors.

"We probably didn't deserve to win in the end, but I thought we had pretty good supply and over 60 inside 50s and dominated clearances but didn't convert those shots early and that hurt us in the end," Simpson said.

The Eagles (10-2) slipped from top spot on the ladder following their second loss to the Swans but can regain the lead with victory over John Worsfold's Essendon outfit, which has lost seven straight in Perth.

West Coast is expecting another crowd in excess of 50,000, despite the match starting at 6.10pm.

Simpson called on supporters to arrive as early as possible and, in doing so, couldn't resist a sly dig at critics of the Eagles' favourable free kick count at home – headlined by St Kilda coach Alan Richardson, who coined the term 'noise of affirmation' in reference to West Coast fans. 

"The louder we can be, the more free kicks we'll get, apparently," Simpson said.