Stammen started his career in the North Star Little League, a small community based league that fostered the development of fellow standout Cory Luebke. Stammen is a graduate of Versailles High School where he played football, basketball and baseball. He was named to the all-Miami Valley baseball team and was awarded Academic All-Ohio honors in 2002. He attended the University of Dayton, where he majored in entrepreneurship and business management and made 60 pitching appearances over three seasons, as well as pitching in the Great Lakes Summer Collegiate League in 2004. He was an Atlantic 10 Conference Academic All-Conference Pick in 2005. On May 19, 2006, he was elected a member of "UDLegends", an association of the most renowned and respected graduates of University of Dayton.

Stammen was selected by the Washington Nationals in the twelfth round of the 2005 Major League Baseball Draft and was assigned to the Vermont Expos of the short-season Single-A New York–Penn League. He made seven starts and six relief appearances, accruing an ERA of 4.06 while striking out 32 batters and allowing 12 walks and 62 hits over 51 innings.

In 2006 Stammen pitched for the Savannah Sand Gnats of the low Single-A South Atlantic League and for the Potomac Nationals of the advanced Single-A Carolina League. In 143 innings he accumulated a 4.03 ERA and struck out 109 batters while allowing 36 walks and 144 hits.

...
Wikipedia