Before entering professional baseball, he played at Cottonwood High School, Salt Lake Community College, and the University of Utah.

On April 15, 2004, Shelton made his major league debut with the Detroit Tigers as a pinch hitter against the Toronto Blue Jays.

He also became the fourth player in baseball history to hit at least nine home runs in his team's first 13 games; he trails only Mike Schmidt in 1976, Larry Walker in 1997, and Luis Gonzalez in 2001 in that regard.

[4] Shelton's power dropped significantly after April, however, and on July 31, 2006, he was optioned to Triple-A Toledo to make room for Sean Casey, whom the Tigers had acquired from Pittsburgh in a trade-deadline deal.

On December 5, 2007, Shelton was traded to the Texas Rangers for Freddy Guzmán, and on January 14, 2008, designated for assignment in order to make room for Kazuo Fukumori, a veteran reliever from the Japanese leagues.

He batted .460 during 2009 spring training (.534 OBP, .720 SLG), second on the team among players with at least 30 at-bats, but did not break camp with the major-league club.