Verthein's first professional season was a short but effective one for the Gary SouthShore RailCats as he made one start and went five and a third innings, giving up two runs (one earned) on two hits. Verthein competed collegiately at University of Wisconsin-La Crosse. His senior season at La Crosse saw him post a 3.86 ERA with a team-leading 72 and a third innings and four complete games. The Freedom traded 1B Jeremy Hamilton for Verthein on December 19, 2013.