The Western Bulldogs face a nervous wait to learn the full extent of star forward Sam Darcy's knee injury amid the carnage of the most "traumatic" night of Luke Beveridge's coaching tenure.

Darcy went down clutching his troublesome left knee in the second quarter of the Bulldogs' 19.17 (131) to 8.8 (56) defeat to Geelong at GMHBA Stadium on Friday night.

Tom Liberatore (concussion), Rory Lobb and James O'Donnell (both hamstring) were also hurt in a horror outing as the Dogs (4-2) slipped to a second straight loss.

Darcy fell to the ground under no contact and there are again fears he has torn an anterior cruciate ligament, which would rule him out for the rest of the season.

The 22-year-old was fortunate to dodge that injury when he hurt the same knee in April last year, though an impaction fracture and associated ligament damage sidelined him for two months.

"I just gave him a pat as I came past, I haven't spoken to him," Beveridge said on Friday in his post-match press conference.

"Last time when he hyperextended his knee we thought that was going to be season-ending and it ended up being a lot less than that.

"So it's too early until you actually know to be too morbid about it."

Darcy's father - 226-game Bulldogs great Luke - suffered two serious knee injuries during his decorated career and was sidelined for most of 2005-06.

The first of those occurred at the same Kardinia Park venue almost 21 years ago to the day.

On Friday night, Geelong's coaches box and the 33,200-strong crowd fell eerily quiet when Darcy fell to the ground.

"I can't imagine their box being any more flat than ours when Sam Darcy went down," Cats coach Chris Scott said.

"You're not a real football person if your heart doesn't go out to individuals and the club in situations like that.

"It's easy to not get carried away with our performance when you think about the challenges the opposition had."

Beveridge forecast Jedd Busslinger and Ryan Gardiner would replace key defenders Lobb and O'Donnell for the Bulldogs' clash with Sydney next Thursday night.

Ruck star Tim English (knee) is no certainty to return, while Liberatore is sidelined again after he had only just returned from a hamstring injury.