The Diamondbacks optioned Rivera to Triple-A Reno on Saturday.
Rivera hasn't recorded a hit since the end of July, so he'll head back to the minors in order to right the ship. Rivera has had better luck in Triple-A this season, slashing .348/.378/.591 in 74 plate appearances, so he could make a quick return to Arizona if he gets going at the plate again. Buddy Kennedy was selected from Reno to take Rivera's spot on the active roster.