Essendon coach James Hird has revealed star quartet Dyson Heppell, Jake Carlisle (ankle), Dustin Fletcher (groin) and Michael Hurley (ankle) were close to being passed fit for Saturday's clash with bottom side Greater Western Sydney at Etihad Stadium, but just hadn't completed enough training this week.

Hird said the players had simply not done enough work during the week to prove their fitness.

‘We have had a philosophy this year that we will play players that are one hundred per cent fit, that had done the required training and those players hadn't.”

"Michael (Hurley) is very upset with me that he is not playing but we wanted to make sure one hundred per cent that his ankle is right."

Hird expects them, along with the suspended Patrick Ryder, to be available for next week's blockbuster against the also-undefeated Geelong, but added: "That's a lot to bring into a team though, so we'll see what happens."

The coach said the rested Jason Winderlich was being carefully managed after playing "five or six games in a row".

"(With) his body, it's been two years since he's played some consistent football, and I think that's the right way to manage a player like Jason, who's such an important player for us," he said.

"I thought (on) Anzac Day his ability to control the forward line and obviously kick goals was really important to us. If we can get 15 to 16 games out of Jason for the year and not get him injured, that's great for both us and Jason."

The Bombers coach confident a ten day break between games would not halt the momentum of the team currently sitting at 5-0.

“It has been a good break, a ten day break between games which is ideal for getting some good quality training in… so we think we are ready to go and there is no lack of motivation for us to play well.”

Hird said he'd be surprised if his team's performance suffered as a result of players becoming distracted by their imminent interviews with ASADA.

Essendon players will soon be interviewed by ASADA investigators as part of the ongoing probe into doping claims, but their coach has faith in their mental toughness to remain focused on reproducing their best football.

"These guys have been so focused, they've been so committed to their football, (and are) such a tight group of players that I'd be surprised if that does take their eye off the ball," he said.

The Bombers mentor said he didn't think the ongoing saga was affecting the players' output.

And he wasn't prepared to predict whether it would eventually take a toll on them.

However, when asked if the off-field situation might be helping the Bombers stay focused, Hird said: "Oh, I wouldn't have thought this is helping."

Despite it all, the Bombers are undefeated and considerable percentage clear at the top of the AFL ladder. Asked whether he had to keep his players grounded, Hird had a wry chuckle.

"I don't think they need any grounding right at the moment," he said. "The environment we're in, they just enjoy playing the best football they can."