Essendon and Hird will find out before Justice John Middleton at 1.30pm on Friday whether they have been successful in having the joint investigation by the Australian Sports Anti-Doping Authority and the AFL into the club's 2011-12 supplements program deemed unlawful.

Legal sources said on Thursday that Middleton would almost certainly just read a summary of his decision, which could take about 15 minutes.

There has also been speculation this week that Stephen Dank – the sports scientist at the centre of the supplements storm who has been issued with a show-cause notice – could appear in court to hear Middleton's decision.

If Middleton does not deliver the relief Hird wants, including having the show-cause notices issued to 34 current and former players at least temporarily voided, then the Bombers coach will face a major fight to retain his job should those players ultimately receive infraction notices.

Of the key personnel who were at the club when the scandal broke in February last year, Hird is the last remaining.

Sports lawyer Darren Kane, who represented Cronulla in the NRL doping saga, said all three parties needed a positive result.

Middleton could find a middle ground, deeming certain parts of the probe illegal but still allowing ASADA to reissue show-cause notices if it has the mettle.

If ASADA were to lose, it could yet be subject to a parliamentary investigation.

"For their own reasons, they all need it [a positive finding]," Kane said. "This thing has been going on for the best part of two years now.

"From ASADA's perspective, given their time again, they would have been much more circumspect about what was disclosed publicly and when, because it has caused them no end of bother having this public aspect of it all. It hasn't helped anything. In my view, it has been completely counterproductive.

"For obvious reasons, job security included, James Hird needs a victory. Essendon, they will be decimated if the end result is that however many of their players are prevented from playing for a period of time.

"One of the options open to his honour is to find there were perhaps departures from what ASADA had to do or the way they had to do things, but you can still say he is not going to grant the relief that James Hird and Essendon are looking for."

However, lawyer Martin Hardie, now a lecturer at Deakin University, believes Essendon and Hird should be "reasonably confident" of a favourable decision.

"It will depend on how much of the evidence, or how much of the material, goes because of validity," said Hardie, who is writing a book on the scandal. "But, on the other hand, administrative law is pretty clear on that – if something is invalid, everything is invalid.

"Then the question is, will ASADA appeal? Clearly if Essendon lose they will have to appeal, because I think the law is pretty clear in this area."

Another senior lawyer who has followed the case closely said the "Bombers had presented their case very well".

Should the show-cause notices stand, players would be given 14 days to respond to allegations they were given the banned peptide Thymosin beta 4 and to declare why they should not be placed on the register of findings. This development would be a major step towards the AFLissuing infraction notices.

"I can't imagine that it's likely that he [Hird] could continue to perform his job at that club if a number of players who were under his care at the relevant time are found to have committed anti-doping rule violations," Kane said.

"I think that becomes a very difficult thing for him, at the very least from a human dynamic point of view. How does he continue to be the best person to coach those players? Maybe it's a question only he can truly answer."

Essendon great Tim Watson, the father of club captain Jobe and the man who helped usher Hird in as coach in 2011, suggested in June that Hird would struggle to retain the top role should infraction notices be issued.

"I think that will depend on whether or not this becomes as messy as infraction notices being handed to players and players being banned from the game," Watson said when asked whether Hird should coach again.

The Bombers are set to announce Mark Thompson, the caretaker coach last season during Hird's 12-month ban, will remain at the club next year in a tactical role.

Kane said the fundamental question Middleton had to answer was whether the joint investigation was unlawful under ASADA's legislation. The anti-doping body and the AFL are allowed to share information.

"All this other stuff, once the report got in the hands of the AFL, whether they were allowed to use that report for purposes other than anti-doping purposes, that doesn't, to my way of thinking, make illegal the ASADA investigation," Kane said.

"It may mean that the AFL shouldn't have used the report for what they did in August last year but, aside from the draft picks, those penalties have pretty much been served. That's not what this case is about – the AFL is not a party to proceedings. The court hasn't been asked to make a decision on whether that disciplinary process conducted by the AFL was legal or not.

"That would require another set of proceedings, by Hird and Essendon again."

Middleton is also set to award costs on Friday, although this could be postponed to a later date.

If Hird and the Bombers lose and decide to appeal to the full Federal Court of three judges, it could be at least another six months before the hearing goes ahead.