Muncy (hand) will serve as the designated hitter for Triple-A Las Vegas on Saturday, Martin Gallegos of MLB.com reports.
Muncy fractured his left hand on a hit-by-pitch in mid-April, which led to him being placed on the 10-day injured list later in the month. He started his swing progression in mid-May and has progressed enough in his recovery to embark on a rehab assignment. It's unclear how many minor-league games Muncy is expected to need before rejoining the A's, but he appears to be close to coming back from the injured list.