Former West Coast Eagles footballer Ben Russell Sharp has pleaded guilty to armed robbery and drug trafficking, blaming his descent on a culture of drug abuse at the AFL club he joined as a teenager in 2004.

After a three-year stint with the Perth-based club, where he played only a handful of preseason games, Sharp, now 30, returned to Melbourne with a fierce addiction to cocaine and methamphetamine after allegedly succumbing to pressure from a group of senior players.

Former West Coast Eagle Ben Sharp playing for Werribee in a VFL semi-final against Casey in 2011. Credit:Getty Images

In December 2014, Sharp, his younger brother and another man used a sawn-off shotgun and a pistol during a dawn robbery of a van driver who had collected $287,000 from three McDonald's restaurants in Melbourne's west.

Barrister Peter Kilduff said Sharp's journey from football prodigy to armed bandit had been fuelled by a destructive drug habit that could be traced to his first months with the West Coast Eagles.