The Diamondbacks optioned Holman to Triple-A Reno on Sunday, Alex Weiner of ArizonaSports.com reports.
Holman tossed a scoreless inning in his lone Cactus League appearance to date, but having a pair of minor-league options remaining might have hurt his cause for breaking camp as a member of the Diamondbacks' Opening Day bullpen. With the Athletics last season, the 25-year-old righty made 22 appearances (two starts) at the big-league level, logging a 5.09 ERA, 1.52 WHIP and 17:9 K:BB in 23 innings.