Young Eagle Brady Hough saved from breaking anti-doping laws

West Coast coach Adam Simpson has detailed the reasons behind Brady Hough's dramatic late withdrawal before the side's 101-point loss to Fremantle, saying the young Eagle risked breaching anti-doping rules if he had played.

The first bounce of Saturday night's western derby was delayed by two minutes after the Eagles frantically withdrew Hough just seconds before the scheduled start of the match.

Hough, who has played 29 games for West Coast since his debut last year, had been hit by the flu earlier in the week.

But it was the fact he had taken too many puffs of Ventolin on game day that convinced West Coast's doctors to withdraw him from the match.

Ventolin is commonly used by asthma sufferers to help relax muscles in the airways and increase air flow to the lungs.

"I don't know if six is the limit of puffs you can have ... he had more than six today," Simpson said.

"So I think he merely mentioned it or the docs just quizzed him on it a little bit in the warm-up out on the ground, and to the docs' credit they worked out that if he plays he might be over the legal game-day limit.

"The docs did a great job, because running the risk of playing when he potentially could be over, there's pretty big ramifications."

Simpson said it was an innocent mistake by Hough, who was unaware of the rules.

"It's almost like he'd be fine to play tomorrow. But on game day, there's rules and he was unaware, so we just couldn't take a risk," Simpson said.

"He made a mistake. It wasn't deliberate. There's nothing sinister.

"He was crook all week, and he took too many puffs of his Ventolin. So it just threw us out of whack a little bit. No excuse for the game."

West Coast conceded 17 consecutive goals on the way to suffering their biggest ever derby defeat - 20.14 (134) to 4.9 (33).

It came just two weeks after West Coast beat North Melbourne, and a week after pushing Essendon all the way in a one-point loss.

The derby loss represents West Coast's fifth triple-figure defeat this season.

"You can ask those questions, that's fine, that's your job," Simpson replied when asked if he thought the derby defeat could put his position in doubt.

"I can't control that. What will be will be. But we definitely took a step back today."

Eagles forward Oscar Allen appeared to injure his right elbow late against the Dockers.

Allen is also battling a shoulder injury, but Simpson isn't worried about long-term damage.

"Whatever he's got, he needs a rest and probably needs a clean-up here and there," Simpson said.

"But they're not major, they're just stingers I suppose that take a few days to recover from, or a few minutes really."