Kelly was outrighted to Double-A Bowie on Thursday, Roch Kubatko of MASN Sports reports.
Kelly will remain in the Orioles' organization after being designated for assignment by the team earlier in the week. The 25-year-old split time with Double-A San Antonio and Triple-A El Paso in 2017, compiling a combined 4.19 ERA across 126.2 innings. He'll serve as organizational pitching depth for the Orioles.