After playing with the Airdrie Extreme in 1997–98, Aulin joined the Kamloops Blazers of the Western Hockey League as 16-year-old in 1998–99, netting 26 points in 55 games and a trip to the league finals. After leading the league in points through nine games, he played through an ankle injury which made his production dip, finishing with 55 points during the 1999–2000 season (57 games), attracting the attention of the Colorado Avalanche, who drafted Aulin in the second round (47th overall) of the 2000 NHL Entry Draft. In the 2000–01 season with the Blazers, Aulin scored a team leading 108 points in 70 games. During this time Aulin's rights were traded by the Avalanche to the Los Angeles Kings in an exchange that saw Rob Blake head to Colorado on March 22, 2001.