Muncy was recalled from Triple-A Nashville on Tuesday.
With Josh Phegley headed to the disabled list, the A's were in need of a good bat off the bench, and that's exactly what Muncy can offer. He's played well with the Sounds so far this season, posting an .858 OPS with six home runs and 15 RBI, and even swiped three bases to boot, so although he'll likely have a limited role as a reserve, he could force Oakland's hand if he can translate those numbers to the big leagues.