Gilmartin, 23, entered the season ranked as the Braves' No. 4 prospect (per Baseball America) heading into the 2013 season. Though he suffered a down year, BA still ranked him 10th among Braves prospects, and MLB.com's Jonathan Mayo kept his ranking strong at No. 4 despite the poor season.
Gilmartin struggled through injuries and posted a 5.06 ERA across three levels in 2013, averaging 6.9 K/9 and 2.8 BB/9 in a total of 105 innings. Selected with the No. 28 overall pick in the 2011 draft, Gilmartin draws praise for his polish from both BA and MLB.com. BA writes that his 89-91 mph fastball has good movement and is complemented by a plus changeup and a slider with "sharp, late break." According to Mayo, "[Gilmartin's] ceiling is somewhat limited, but he's not far from being ready to step in as a middle-of-the-rotation type in the big leagues."