Before Union: Key prepped at Jackson Christian School where he played baseball and football. He helped his baseball team win the 2008 Tennessee State Title. Key was a two-time all-state player, district MVP, all-region, and was selected the MVP of the Senior All-Star Classic. Key hit .502 with three home runs as a sophomore, .392 with 10 home runs as a junior, and .476 with 15 home runs as a senior.