Stein was a left-handed pitcher who was drafted by the Arizona Diamondbacks in 2004, and he spent two years in their farm system. In 2004, he pitched for the Missoula Osprey in the Pioneer League. In 2005, he was with the South Bend Silver Hawks, helping his team win the Midwest League championship.

In 2006, he played for the Gateway Grizzlies in the Frontier League under manager Danny Cox. From 2001 to 2004, Stein pitched in the Missouri Valley Conference for Illinois State University in Normal.

During the summer of 2001, he was a pitcher for the Twin City Stars, a team representing the twin cities of Bloomington and Normal in the Central Illinois Collegiate League.

During the summer of 2000, he played for St. Charles in the St. Louis Metro Collegiate League. During the summers of 2002 and 2003, he pitched for Creve Coeur in the St. Louis Metro Collegiate League. He was named to the Metro League all-star team all three years.

Stein was an outstanding pitcher at Ladue Horton Watkins High School from 1997 to 2000. His senior year, he pitched a no-hitter against Brentwood High School. He set a school record with sixteen strikeouts in the 6-1 victory. He only walked three batters, and the one run allowed was unearned. 

He was named to four American Legion all-star teams while pitching for the Goff-Moll Post 101 team in Brentwood. Stein is currently the owner and manager of the St. Louis Recruits Baseball Club which has approximately thirty youth teams for ages eight to seventeen.