The Athletics recalled Muncy from Triple-A Las Vegas on Tuesday.
With Joshua Kuroda-Grauer (groin) facing an extended stay on the injured list, Muncy will rejoin the big club to bolster its infield depth. The 23-year-old owns just a .699 OPS through 175 plate appearances in the majors this season, but he's gone 7-for-20 with two homers, five RBI and five runs scored in five games since his demotion to Triple-A on July 8. He and Tommy White will likely compete for starts at the hot corner until Kuroda-Grauer is healthy.