Yunior Marte was 17 when the Royals signed him out of the Dominican Republic in 2012. He began his professional baseball career with the Dominican Royals of the Dominican Summer League (DSL) in 2013. That year he was the Dominican Royals Pitcher of the Year after going 4-3 with an ERA of 1.71 in 47.1 innings over 11 appearances, including eight starts.
From the beginning of his career in 2013 and into the 2016 season he was primarily a starter. During the 2016 season he became primarily a relief pitcher and has made 55 relief appearances since then while only making only 8 starts. Marte started the 2017 season with the Wilmington Blue Rocks before earning a promotion to AA Northwest Arkansas Naturals where he struggled a bit. He was a midseason Carolina League All-Star and even with his struggles he still struck out 80 batters in 72.1 innings with a 3.98 ERA between High-A and AA, though he did have a high walk rate. He features a power fastball up to 97 mph with a plus changeup & two seam fastball.
Although he is the type of pitcher that gets selected in the Rule 5 draft, he was left unprotected by the Royals in 2017 and slipped through unscathed. He is currently ranked as the Royals #38 prospect by Royals Farm Report. In 2013 he received the Carlos Fortuna Award which is given to a player who is dedicated to improving his English skills, his genuine work ethic for advancing his physical talents, and outstanding conduct demonstrated on and off the field while representing the Royals. Fortuna was a Royals pitching prospect who died of liver and lung cancer at age 22 in 2013 just before his 23rd birthday.