Kelly was optioned to Triple-A Norfolk on Tuesday, Roch Kubatko of MASN Sports reports.
The 25-year-old righty had success in 84.2 innings for Double-A San Antonio in the Padres' system last season, putting up a 2.98 ERA with a 26.5 percent strikeout rate. He hit a wall upon promotion to Triple-A El Paso, though, with an ERA that ballooned to 6.64 and a strikeout rate that sunk to 18.7 percent. If he can conquer the Triple-A level this season, he could be in line for a summer promotion to the majors.