Two years into his three-year major junior career with the Western Hockey League (WHL)'s Medicine Hat Tigers, Lupul was drafted by the Mighty Ducks of Anaheim as the team's first choice, seventh overall, at the 2002 NHL Entry Draft. The London Knights' Rick Nash was chosen first and Lupul's Tigers teammate Jay Bouwmeester went third that year. The following season, Lupul made the final roster for Canada and played in the 2003 World Junior Ice Hockey Championships in Halifax, Nova Scotia.