harrison was drafted by the milwaukee brewers in the second round of the 2014 major league baseball draft. he signed with the brewers on june 14 and was assigned to the azl brewers where he posted a .261 batting average with one home run and 20 rbis, along with 32 stolen bases, in 50 games. harrison began 2015 with the wisconsin timber rattlers, and after batting only .148 with 11 rbis in 46 games, he was reassigned to the helena brewers, where he finished the season and where he posted a .299 average with three home runs and 13 rbis in 28 games. in 2016, he returned to the timber rattlers and spent the whole season there, batting .221 with six home runs and 37 rbis in 75 games. harrison spent 2017 with both wisconsin and the carolina mudcats and posted a combined .272 batting average with 21 home runs, 67 rbis, and 27 stolen bases in 122 games between both clubs.