The Bombers trained on Wednesday morning and coach Hird said he hoped the club could "move on" with its business despite the scandal.
"Our players are moving on, we're training hard and we're looking forward to the start of the season.
"I'm sure it (the allegations) does have an effect (on them), but we're moving on."
Essendon scandal FAQs
The Bombers trained at Tullamarine, attempting to go about their business as usual despite an unprecedented doping cloud hovering over the club.
Players were greeted at the car park gate by a security guard and club officials, preventing news crews from seeking comment.
A joint investigation between the Australian Sports Anti-Doping Agency and the AFL's integrity department is now underway.
The investigation focuses on allegations that banned substances were being mixed with supplements, which were being given to players in tablet, injection and intravenous form.
It's understood all players on Essendon's 2012 list will be questioned as part of the investigation.
We knew it was on the edge: Reimers
Players and officials have been warned not to publicly comment because they could compromise the inquiry.
Under the World Anti-Doping Agency code any player found guilty of using performance enhancing drugs faces an automatic two-year ban. There is the capacity to argue mitigating circumstances.
As revealed exclusively by AFL.com.au on Tuesday night, Essendon stood down fitness guru Dean Robinson pending the investigation.
Robinson's right hand man sports scientist Stephen Dank parted ways with the club late last year.
Dank had previously worked with Robinson at the Manly NRL club, where he was known to have used some contentious techniques.
The pair then worked together again at Gold Coast.
In other developments:
- ASADA has called on any potential witnesses to come forward
- Essendon legend Tim Watson said he'd be "absolutely devastated" if his son Jobe Watson lost his Brownlow Medal
- There are reports players were headed off-campus to receive injections of unknown substances
- Brownlow medallist Gerard Healy revealed he raised concerns with former AFL football operations manager Adrian Anderson after a tip-off 12 months ago
- There's speculation at least one other AFL club could become caught up in the investigation
- Geelong distanced itself from former employee Robinson saying it had "no evidence" of any wrongdoing during his time at the club
- Gold Coast said Robinson and Dank worked only "briefly" at the club, and it was willing to cooperate with the investigation
- The AFL Players' Association said concerns about clubs giving directions to players regarding supplement use should be treated with the "utmost seriousness."
Timeline: Essendon from 2011 to 2013
The investigation is set to focus on a number of factors, including the type of substances allegedly used, waiver documents players were supposedly asked to sign and the Bombers' high injury toll during the 2012 season.
More than half of the club's playing list suffered some kind of soft tissue injury last season, predominately hamstring related.
It is believed 'peptides' – the type of substance reportedly used – have an ability to promote muscle growth, but soft tissue injuries can be a symptom.
Banned growth hormone GHRP6 is one such peptide.
Players weigh in on scandal
After morning meetings at AFL House on Tuesday, Essendon chairman David Evans told an afternoon press conference that the Bombers had received information in the preceding 48 hours raising concerns about the supplements.
Evans said the Bombers had contacted the AFL and ASADA to launch an immediate joint investigation.
"Of course this is a very distressing time for our club, our executive, our players and our board. We believe as a club that we have done everything right to be compliant with the rules and regulations of the AFL and ASADA," he said.
"But the integrity of the club is critical to the people sitting at this table and, of course, for the broader Essendon family. And that is why we have moved quickly today to call the AFL and ASADA to seek a clean bill of health.
"The info we gathered over the last 24 or 48 hours is slightly concerning, and we want to dig a bit deeper but we want the AFL to help us."
Evans was accompanied at the press conference by Essendon CEO Ian Robson and coach James Hird.
"I'm very disappointed, shocked is probably the best word," Hird said.
"As a coach I take full responsibility for what happens in our footy department.
"If there have been goings on within our football department that are not right we want to know.
"But it's my belief, though, that we have done everything right and that … the supplements that our players were given … were all approved and within the regulations that we all play the games by."
Evans refused to directly answer questions on the nature of the information Essendon had received about the supplements, where that information had come from, and whether it raised concerns about performance-enhancing drugs.
Dons players' legal threat
Acting AFL football operations manager Gillon McLachlan said the Bombers had acted appropriately in seeking an investigation.
"David Evans has briefed the AFL about the matter and we support his actions," McLachlan said.
"The AFL's integrity unit already works closely with ASADA and will assist with the investigation."
