Armstrong joins LaMelo Ball, RJ Hampton, and KJ Martin as the fourth prospect from the 2019 class to forgo their college eligibility and head elsewhere to play pro.
Questions had circulated as to whether the four-star prospect would receive the requisite grades to be eligible for school, according to Rivals.com's Corey Evans.
The 6-foot-6 wing was recruited by multiple high-profile schools before ultimately committing to Arizona in October 2018. The Wildcats still have two five-star prospects and a pair of four-star players committed for next season, including McDonald's All-American point guard Nico Mannion.
Armstrong averaged 20.4 points on 49.4 percent shooting from the floor - including 35 percent from distance - adding 5.3 rebounds per contest across 12 Nike EYBL games.