Barker was a 16th round selection by the Braves from Mercer University in Macon, Georgia in the 2014 draft. The Braves sent the 21 year-old to advanced-rookie Danville of the Appalachian League for just two games before promoting him directly to A-ball and Rome. He finished the season as a swing man for the R-Braves, pitching in 12 games, and starting 5 of them. Overall, he had 36 1/3 innings pitched in 2014 with a 3.72 ERA and 1.46 WHIP. He also posted a 12/34 BB/K ratio.
Barker was moved full-time to the rotation to start 2015 in Rome, and he didn’t do anything remarkable, but he was simply incredibly steady, earning his way to a midseason promotion to high-A Carolina, and even making a pair of fill-in starts for AAA Gwinnett.