THE AFL Players' Association says it is "premature and unfair" to suggest Jobe Watson should lose his Brownlow Medal or be stood down, and that accountability for the supplements crisis should rest with Essendon.

AFLPA CEO Matt Finnis says the ongoing ASADA and AFL investigation into the Bombers' supplements program will determine if rules have been broken but has pointed the finger squarely at the Bombers as the ones responsible. 

"Accountability must reside with those who had the ultimate authority and responsibility, and I think the public confidence in the competition and the codes and rules which govern it absolutely demands that," Finnis said on Wednesday. 

"Quite clearly, there have been failings here at the club.

"Whilst players have a responsibility in relation to their part in this process, culpability must reside with those who had the ultimate authority; with those who's trust the players place in being able to guide them through what is an increasingly complex and highly regulated area."

Watson admitted on Monday night's On The Couch he had taken banned anti-obesity drug AOD-9604 but believed he had done nothing wrong.

I took banned drug: Watson

Finnis said the AFLPA understood the Essendon players had done "everything they could" in taking positive steps to make sure the supplements they took last year were legal.

The players asked the club to put in writing what they were taking.  

Finnis said the Bombers had "put the interests of performance ahead of the broader welfare of the playing group".

He also said the players were in "a very untenable situation" because of decisions made by the club.

As a result, he said it was hard to see how players could be punished for taking the banned supplement.

"We understand the concept of strict liability and personal responsibility, but I don't think we can also ignore the principals of fairness and justice," he said.

"Any system which would seek to place heavy penalties on somebody who has acted in accordance with the directions of their employer as they're required to do under their contract, and has been the victim of some kind of misrepresentation or even deception … would be completely unacceptable.

"That's why we'll continue to represent the players to avoid that situation arising."

How the Bombers might argue their case

Finnis said the AFLPA had not advised players on what they should say when questioned by the media.

He said Watson's admission, which has sparked debate over whether he should be suspended or stripped of his 2012 Brownlow Medal, was "a reflection of his character". 

"Jobe gave full and frank and honest answers," he said.

"Jobe's done a five-minute interview. There's been a five-month investigation. He's also co-operated with the investigation for two to three hours.

"All of the players have been thanked by ASADA, they've been congratulated for their openness, their candour and their co-operation.

"Given that we all want to get to the bottom of this, people should be encouraged by that."

It is understood that players who were at Essendon in 2012 but are no longer on the club's list received a text message from the AFLPA on Tuesday asking them not to comment on what they may have told investigators.

Along with Essendon and the AFL, the players' association is concerned isolated comments will otherwise be viewed out of context.

Watson's comments also raised questions about the role of Dr Reid in Essendon's supplements saga, given that the player indicated he took the substance because the club doctor had approved it.

The president of the AFL Medical Officers' Association, Dr Hugh Seward, said Dr Reid remained highly regarded within the industry and a person of great integrity.

"We look forward to that being clarified with the outcome of the findings," Dr Seward said.

However, he admitted he had no awareness of the substance AOD-9604 until the ASADA inquiry began.

"I had never heard of it until this whole issue was raised so it [was] certainly not of mainstream interest to anyone until all this has come out," Dr Seward said.

Jennifer Phelan is a reporter for AFL Media. Follow her on Twitter @AFL_JenPhelan.