Olivero is 25 years old and hails from the Dominican Republic. The hurler was signed on with the Arizona Diamondbacks as an international free agent. He started his professional career in 2016 at the age of 18.  

Olivero would go on to be recognized as an All-Star in 2018 and 2019 and was named the Northwest League Pitcher of the Year as a member of the Hillsboro Hops. That year he went 8-3, with an impressive 2.09 ERA, and struck out 42 batters.  

The northpaw made it as far as Triple-A in the Diamondbacks organization, and in seven years with Arizona he appeared in 100 games in which 87 of them were starts.