WEST Coast was forced into a last-minute change ahead of Saturday night's disastrous Western Derby loss when it became clear defender Brady Hough was at risk of breaching the permitted limits for an asthma medication. 

The clash at Optus Stadium was held up momentarily pre-game when the Eagles' doctor recognised that Hough, who had been ill during the week with the flu and trained away from teammates on Friday, may have inadvertently gone over the game-day limit for Ventolin use. 

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The inhaled medication is only allowed to be used six separate times in an eight-hour period on game day, or 16 times over 24 hours, according to Sport Integrity Australia, with Hough unaware of the limits. 

The second-year Eagle appeared apologetic when talking to Simpson on the bench as the opening bounce was held up, with emergency Jack Williams called into the 22 as play was due to start.   

"He has Ventolin and he took too many puffs on game day and I think there's a level you can go to before it becomes too many. He was unaware of how many you can take," Simpson said after the loss, which was West Coast's heaviest in Western Derby history.

"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. 

"I'm speaking a little bit out of school because I don't know the complete detail, but he had more than six today. So, 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.

"Running the risk of playing when he potentially could be over, there's pretty big ramifications."

Simpson stressed that Hough had simply made a mistake and was unaware of the rules when using Ventolin on game day, with the 20-year-old joining Jack Petruccelle, who had tonsilitis, as a late out. 

Simpson said the pre-game issues were no excuse for the Eagles' performance, with the team taking a step backwards in what was the most one-sided derby in more than 20 years. 

"You get what you deserve. We weren't strong enough around the ball. We coughed it up and we didn't manage it at all," Simpson said. 

"They were too tough for us tonight. And it's not good enough. We need to work on it, and we had 51,000 fans and they've just turned up every week. So to let them down, as well as each other, I think they're really disappointed.

"We've got a couple of weeks to go, and we've got a choice as to how we want to handle it. We'd like to finish it off as well as we can."

Asked if he was worried that a 100-point loss in a derby could be the tipping point that forces West Coast into a coaching change, Simpson said: "I can't control that, so what will be will be. But we definitely took a step back today."

Fremantle coach Justin Longmuir described his team's ability to apply pressure, win contests and defend the front half as "A-grade", playing long periods of the game in its front half and dominating the inside 50s (64-35). 

"When we play our best footy, we get our contest right, we get our stoppage work right and we get the ball in and we defend really well behind it," he said. 

"We haven't been consistent enough for that by any stretch this year. But yeah, that's the brand we want to play."

Longmuir said a second Glendinning-Allan Medal for small forward Lachie Schultz was "reward for effort", with the dynamic Docker booting a game-high five goals and racking up 24 disposals and 11 score involvements. 

He said young key forward Jye Amiss should figure prominently as an AFL Rising Star contender after booting four goals and taking his season tally to 38. 

"I think he should be a really good chance … I'm surprised he's not mentioned up there as being one of the favourites," he said.

"Carrying the load as a key forward as a second-year player, to kick that many goals is a really good effort. So yeah, I'm surprised he's not mentioned as one of the favourites."