Lee Mapals, the former Keighley and Hunsley player, has been banned for four years following an Anti-Doping Rule Violation (ADRV).
Mapals, who played for the Hawks this season, tested positive for the anabolic steroid nandrolone and metabolites of the steroid oxymetholone following an out-of-competition test on 16 June 2016.
The 31-year-old is currently in his second spell at the Hawks, have re-joined the club at the start of the season from Newcastle Thunder.
UKAD Director of Operations, Pat Myhill said: “Testing positive for the presence of multiple Prohibited Substances is a serious breach of the anti-doping rules and the spirit of sport.
“When Lee Mapals made the decision to dope, he also chose to cheat his teammates, his opposition, his fans and his sport. At the same time, his actions risked not just his career, but his reputation and health.
“UKAD will always seek to impose the maximum possible sanction on any individual who decides to consciously cheat the system. I hope that this case acts as a deterrent to others who are considering the use of performance-enhancing substances.”
Mapals is banned from all sport from 8 July 2016 until 7 July 2020.