Former Hull centre Martin Gleeson, chief executive James Rule and conditioner Ben Cooper have been banned for breaching anti-doping rules.
UK Anti-Doping today revealed Gleeson, 31, tested positive for a prohibited substance in May and had accepted a three-year ban, half of which will be suspended.
Rule and Cooper were found to have conspired with Gleeson to cover up the circumstances surrounding the positive test and have also been punished. Rule has been suspended for two years and Cooper for two with one suspended.
All three men have left Hull since the offence took place.
A statement from UKAD, who administer drugs tests on behalf of the Rugby Football League, read: "Mr Gleeson agreed to a three-year ban being imposed by the National Anti-Doping Panel, with half that ban suspended in recognition of his providing assistance to UK Anti-Doping.
"Mr Cooper agreed to a two-year ban, with half also suspended.
"Mr Rule did not contest the charge made against him by UK Anti-Doping, and has been banned for two years by the National Anti-Doping Panel."
The statement casts further light on Gleeson's brief stint at the KC Stadium.
The former Great Britain international joined Hull on an 18-month deal after being released by Wigan in April but made just seven Super League appearances.
He played his last game against Harlequins on June 12 having tested positive for the banned stimulant methylhexaneamine after a game against Salford on May 13.
His subsequent absences from the team were attributed to a stress-related illness and the player's contract was later terminated in September.
His ban will be backdated to June 2011 but will not expire until November next year and leaves him facing an uncertain future in the game.
Gleeson has been one of the country's best three-quarters during a career which has also included spells at Huddersfield, St Helens and Warrington.
However, he has also been involved in controversy and was banned for his part in a betting scandal in 2004 and dropped by Wigan for disciplinary reasons last year.
UKAD chief executive Andy Parkinson said: "This case marks two firsts for the anti-doping community.
"It is the first time that tampering with the doping control process in this manner has resulted in a violation, and the first time that members of an athlete's entourage have been convicted of anti-doping rule violations in the UK.
"In a hearing before the National Anti-Doping Panel, athletes and their entourage are obliged to tell the truth, or the system will fail, and this case makes clear the penalties for not doing so.
"Once again, this highlights to the sporting community that UK Anti-Doping will aggressively pursue all types of anti-doping rule violation.
"While all eyes are on the London Games this year, we continue to work on behalf of clean athletes in every sport.
"I would like to thank the RFL for their support and assistance throughout this process which has reinforced rugby league's ongoing commitment to tackling the issue of doping in sport."
The RFL believe the case highlights their strong anti-drugs policy.
Chief executive Nigel Wood said: "Such behaviour is unacceptable and this case has brought the sport of rugby league into disrepute.
"We must applaud UK Anti-Doping for the hours of work they have put in to conduct a detailed and extensive investigation.
"We have assisted UK Anti-Doping throughout their investigation and these results show that doping of any kind will not be tolerated in our sport."
Hull have not yet commented on the issue.