Oliva was optioned to Triple-A Indianapolis on Saturday, Alex Stumpf of DKPittsburghSports.com reports.
Oliva shifted to a bench role recently, and he had started just two games since the All-Star break. In nine appearances during that time, the 25-year-old went 3-for-13 with two runs and an RBI. He should see more consistent playing time in the minors, while Hoy Park will take his place on the active roster.