Keller was selected by the Reds with the fifth pick in the Rule 5 draft Thursday and then dealt to the Royals for cash considerations, Jeffrey Flanagan of MLB.com reports.

A 22-year-old righty, Keller posted a 4.68 ERA, 1.52 WHIP and 111 strikeouts in 130.2 innings at Double-A last season. He projects as a No. 5 starter, at best, but he has significant experience in the upper levels of the minors, which likely appealed to the Royals. He should serve as a mop-up man out of the bullpen this year, as the Royals need to keep him on the active roster all season, otherwise he will be exposed to waivers and offered back to the Diamondbacks.