AFL SPORTS Science Association head Dr Rob Aughey admits he is as surprised as anyone that an AFL club could find itself subject to an investigation into the use of supplements, but says it is too early to speculate as to whether the Bombers had broken any rules.  

Aughey was responding to Tuesday's shock announcement that the Bombers had called for an independent investigation to be held into the club after it received information that raised questions about the use of supplements by players during 2012.

He said until more information came to light, it was tough to comment. But he added he was confident the authorities would discover exactly what had occurred.  

"We do have complete confidence in ASADA and the AFL to get to the bottom of what happened," Dr Aughey said.

"Whether there was something that contravened the rules or not, we don't know that yet.

"I guess we're in the same boat as a lot of people. Until those organisations complete their investigations, we really don't know what, if anything, happened."

Most AFL clubs have strict protocols in place in relation to the use of supplements. Players are provided with a list of approved supplements that are compliant with ASADA guidelines. Any player who wishes to take a supplement that is not included on that list must receive authorisation from their club doctor and sports science director to ensure it sits within the guidelines.

The directions are clear, and the players are made acutely aware of what is acceptable.

Essendon coach James Hird had earlier told the media he believed the club worked within the framework that was given to the Bombers by the AFL and the World Anti-Doping Authority (WADA).

"I'm shocked to be sitting here to be honest," Hird said during Tuesday's press conference.