In 2003-04, Winnipeg native Cam Barker netted a career-high 65 points in 69 games and 12 in 20 post-season contests, helping the Medicine Hat Tigers take home the WHL championship. But despite being chosen to play for Team WHL at the annual Canada/Russia Challenge Series, Barker surprisingly did not receive an invite to Team Canada's development camp for the World Junior Championships. Instead, he suited up for Canada's entry at the 2003 U-18 World Cup where he only saw sparse duty as the team's seventh defenseman.
The Chicago Blackhawks selected Barker with the third overall pick in 2004.
A serious bout of mononucleosis interrupted Barker's 2004-05 campaign, causing him to be sent home after five games at the World Junior Championships and to miss all but 52 games of the regular season.
Barker also suffered through injury in 2005-2006, playing just 26 games for Medicine Hat, registering five goals, 13 assists and 63 penalty minutes. He did make his NHL debut with the Blackhawks that season, appearing in one game.
After suffering a broken ankle in the 2006-2007 preseason, Barker came back to split the remainder of the regular season between Norfolk (AHL) and the Blackhawks.