''The drug in question was prescribed to him to treat a pre-existing condition and the board and management were unaware of this prescription,'' Davis said in a statement last night.
Davis said Dawson had chosen to stand aside from the team while the B sample was tested, but is now suspended until a Drug Free Sport NZ hearing at a date to be confirmed. Dawson faces a possible two-year ban.
Davis confirmed Dawson was tested out of competition by Drug Free Sport NZ in February 2014 and returned a positive test to a banned substance.
National Basketball League chairman Sam Rossiter-Stead said he believed the Sharks could rebound from what has been a damaging week for the Invercargill-based franchise.
At the weekend, three Sharks players were arrested following a brawl outside a New Plymouth bar. Rossiter-Stead said he could not comment regarding Dawson's failed test.
''Drug Free Sport have made it really clear - we are not to comment on any drug issue and we have to take the lead from them.''
However, when asked if the image of NBL and the Sharks had been tarnished, Rossiter-Stead said the league had been superb this season and the Sharks were an excellent organisation.
''Any negative publicity is a setback but there has been a tremendous amount of work done and the league is in a far healthier state than it was in 2008,'' he said.
''In terms of Southland, obviously there have been two regrettable incidents this year.
''They are far too strong as a franchise for this to have a permanent damaging effect on them. They will survive this and actually be all the stronger for it.
''We are working with them to give them all the support they need. We are confident with the management they have down there that they will put things back on track.''
The other incident Rossiter-Stead was referring to occurred on April 6.
Two Southland sportsmen were arrested and charged with incurring a debt by deception after fleeing from a taxi without paying.
Drug Free Sport New Zealand chief executive Graeme Steel said he ''can't comment'' when asked specifically if Dawson had failed a drugs test.
''The world anti-doping code requires organisations to have all the dealings around a positive test kept confidential,'' Steel said.
''When there is an outcome, that is made public.
''It is not a short process. Normally, after a positive A sample, there is a provisional suspension. The athlete is then taken out of play.''
Dawson has not played for the Sharks since round six. Until last night, his absence had been explained by Sharks officials as a break for personal reasons.
Southland Basketball Association general manager Jill Bolger and Sharks coach Paul Henare did not return messages yesterday.
Dawson (25), who went to Roncalli College in Timaru also had a stint at Waitaki Boys' High School in 2006-07 and made his NBL debut in 2009 for the Manawatu Jets before joining the Southland Sharks for their inaugural season in 2010.
He averaged 7.7 points and 5.5 points that season and returned in 2011.
He transferred to the Nelson Giants in 2012 but returned to the Sharks in 2013 and helped them claim their first NBL title.
Otago Nuggets player-coach Mark Dickel played alongside Dawson at the Sharks in 2011 and said he was surprised by the news.
''It will be a shock for everybody and I'm disappointed for him because he was playing good basketball,'' Dickel said.
''We only have so many good players in New Zealand that are big guys. So it was good to see that he was developing.
''I know in the NBA, you can take stuff to stop your hair falling out and test positive, so, without knowing the circumstances, it is hard to know exactly what went on.''
