Peacock was optioned to Triple-A Buffalo on Thursday, Mitch Bannon of SI.com reports.

EDGE Analysis

Peacock didn't make any appearances during his one-day stint in the big-league bullpen, and he'll head back to the minors as part of a move to make room for Anthony Bass and Zach Pop on the active roster. Peacock has posted a 5.40 ERA and 1.60 WHIP in 10 innings over nine relief appearances between the Diamondbacks and Royals this year.