Amrhein served as the team's backup quarterback during the 2011 season, seeing action in one game. He completed his only pass attempt against Yale for three years. A strong-armed quarterback with excellent footwork, Amrhein missed the entire 2010 season due to a shoulder injury. Amrhein showed great potential in suiting up with the varsity as a rookie. He saw action in the home game against Fordham in 2009, completing 1-of-4 passes for six yards and an interception. Amrhein was listed as the backup on the team's two-deep throughout that season.
On October 13, 2012, he started and beat Monmouth University 41–38. He went 33 of 56, throwing for 523 yards and 1 touchdown. This was the 3rd-highest passing yards in a single game in Ivy League history.
