alexander moved between three levels in the royals farm system in 2013, with five games for the lexington legends of the south atlantic league, 12 for the wilmington blue rocks of the carolina league and 24 for the northwest arkansas naturals of the texas league. overall, he was 5–1 with a 3.00 era and appeared exclusively out of the bullpen. he did not allow a homerun all season and pitched had the second most innings pitched in the minor leagues (75) without a homer. in 2015 he pitched in 35 games for the naturals and 11 for the omaha storm chasers of the pacific coast league. he finished 2–4 with a 4.52 era in 67 innings. he pitched for the gigantes del cibao of the dominican winter league after the season and then returned to omaha for 2015, where he was 2–3 with a 2.56 era in 63 innings over 41 games. the royals selected him as their triple-a pitcher of the year.