The Athletics optioned Muncy to Triple-A Las Vegas on Saturday.
Muncy was brought up from Triple-A on Tuesday to provide infield depth when Joshua Kuroda-Grauer (groin) landed on the injured list, but the former will now head back to the minors following Nick Kurtz's (thumb) return from the IL. Muncy has slashed .223/.298/.389 across 178 plate appearances with the Athletics this season and would likely be one of the first choices to return to Sacramento if the big club's infield depth is tested again down the stretch.