playing for the wisconsin timber rattlers of the class a midwest league in 2012, the timber rattlers won the midwest league championship. in 2013, the brewers assigned shackelford to the arizona fall league, where he was a member of the championship-winning surprise saguaros. after the 2013 season, the brewers added shackelford to their 40-man roster. he was designated for assignment on july 17, 2014, to make room for irving falu.