Dunn was promoted to Double-A Binghamton on Friday, Tim Healey of Newsday reports.
The 19th overall pick in the 2016 draft, Dunn was pretty mediocre in his first full season in 2017, but has reestablished his prospect stock this season. He logged a 2.36 ERA, 1.27 WHIP and 51:15 K:BB in 45.2 innings (nine starts) at High-A, and will look to further increase his stock by producing at a more age-appropriate level.