The Ontario Hockey League (OHL)'s Kitchener Rangers drafted Fowler with their first pick in the 2007 OHL Priority Selection; however, given that he had already committed to Notre Dame and playing in the OHL would have cost him his eligibility to play in the NCAA, Fowler refused to sign with the Rangers and instead made a two-year commitment to play for the USNTDP.
With the development team, he was a member of the gold medal-winning American team at the 2009 IIHF World U18 Championships, where was named the best defenseman of the tournament and an all-star.

The Rangers surrendered his OHL rights at about the same time Fowler was reconsidering his commitment to play in the NCAA.
The Windsor Spitfires then selected him with their first pick in the 2008 Priority Selection, after which he broke his agreement with Notre Dame and agreed to play for Windsor in the 2009–10 season.
Fowler made the decision with the belief that playing in the OHL would better prepare him for an NHL career.
The decision upset University officials, who alleged he was paid "under the table" by the OHL.
Notre Dame Fighting Irish ice hockey team head coach Jeff Jackson alleged that the Rangers had offered Fowler a package worth $500,000 to break his commitment with Notre Dame and believed that Windsor had also made a financial offer to lure him away from the school.
Fowler denied the accusations, stating he was "completely honest" with both Notre Dame and the Kitchener Rangers.

Fowler joined the Spitfires in 2009 and emerged as one of the top offensive-defensemen in the league, scoring 55 points in 55 games.
He added 14 points in the playoffs to help lead Windsor to its second consecutive J. Ross Robertson Cup championship.
The Spitfires then won the 2010 Memorial Cup as Canadian Hockey League (CHL) champions.
Fowler left the Spitfires briefly during the season to play with the U.S. at the 2010 World Junior Ice Hockey Championships, winning a gold medal after defeating Canada 6–5 in overtime in the championship game.

The NHL Central Scouting Bureau ranked Fowler as the fifth-best North American prospect for the 2010 NHL Entry Draft in their final update.
He had dropped two places, having been ranked at number three, behind Taylor Hall and Tyler Seguin, for most of the season.
He was described by the NHL Central Scouting Bureau as an offensive quarterback on the powerplay who relies on his skating and puck control.
He has been compared to NHL defensemen Chris Pronger and Dion Phaneuf, but does not play the same physical style as the two.
Despite these accolades, Fowler's draft night lasted longer than expected, as he dropped to 12th overall, selected by the Anaheim Ducks.
The Ontario Hockey League (OHL)'s Kitchener Rangers drafted Fowler with their first pick in the 2007 OHL Priority Selection; however, given that he had already committed to Notre Dame and playing in the OHL would have cost him his eligibility to play in the NCAA, Fowler refused to sign with the Rangers and instead made a two-year commitment to play for the USNTDP. With the development team, he was a member of the gold medal-winning American team at the 2009 IIHF World U18 Championships, where was named the best defenseman of the tournament and an all-star.
The Rangers surrendered his OHL rights at about the same time Fowler was reconsidering his commitment to play in the NCAA. The Windsor Spitfires then selected him with their first pick in the 2008 Priority Selection, after which he broke his agreement with Notre Dame and agreed to play for Windsor in the 2009–10 season. Fowler made the decision with the belief that playing in the OHL would better prepare him for an NHL career. The decision upset University officials, who alleged he was paid "under the table" by the OHL. Notre Dame Fighting Irish ice hockey team head coach Jeff Jackson alleged that the Rangers had offered Fowler a package worth $500,000 to break his commitment with Notre Dame and believed that Windsor had also made a financial offer to lure him away from the school. Fowler denied the accusations, stating he was "completely honest" with both Notre Dame and the Kitchener Rangers.
Fowler joined the Spitfires in 2009 and emerged as one of the top offensive-defensemen in the league, scoring 55 points in 55 games. He added 14 points in the playoffs to help lead Windsor to its second consecutive J. Ross Robertson Cup championship. The Spitfires then won the 2010 Memorial Cup as Canadian Hockey League (CHL) champions. Fowler left the Spitfires briefly during the season to play with the U.S. at the 2010 World Junior Ice Hockey Championships, winning a gold medal after defeating Canada 6–5 in overtime in the championship game.
The NHL Central Scouting Bureau ranked Fowler as the fifth-best North American prospect for the 2010 NHL Entry Draft in their final update. He had dropped two places, having been ranked at number three, behind Taylor Hall and Tyler Seguin, for most of the season. He was described by the NHL Central Scouting Bureau as an offensive quarterback on the powerplay who relies on his skating and puck control. He has been compared to NHL defensemen Chris Pronger and Dion Phaneuf, but does not play the same physical style as the two. Despite these accolades, Fowler's draft night lasted longer than expected, as he dropped to 12th overall, selected by the Anaheim Ducks.
Cam Fowler