Auburn Doubledays
In 2009, Horsman was the pitching coach for the Blue Jays' short-season Auburn Doubledays. Between 2010 and 2014, he was a part of the Class-A Lansing Lugnuts coaching staff. On December 18, 2014, he was promoted to the (Advanced-A) Dunedin Blue Jays. On January 20, 2016, he was promoted to the Double-A New Hampshire Fisher Cats.