Hunslet prop Nathan Darby has been banned from all sport until February 2020 after failing a drugs test.
Former Featherstone player Darby was suspended after testing positive for three anabolic steroids during an out-of-competition test in January.
The 21-year-old joined League One side Hawks in 2015 after a trial, and signed a new one-year deal in October.
In May, UK Anti-Doping chief Nicole Sapstead spoke of a "worrying trend" of young rugby players using steroids.
Subscribe to the BBC Sport newsletter to get our pick of news, features and video sent to your inbox.