Diamondbacks manager Kirk Gibson said Tuesday the 21-year-old Bauer, a right-hander and former UCLA standout, will be called up from Triple-A Reno and join the team on Wednesday.
Bauer is 4-0 with a 2.82 ERA in eight starts at Reno. He was 7-1 with a 1.68 ERA at Double-A Mobile.
Gibson says "everybody is excited" about Bauer's debut. Bauer is replacing Joe Saunders, on the disabled list with a shoulder injury, in the rotation.
Gibson says shortstop Stephen Drew will be activated off the 15-day disabled list and start Wednesday night. Drew has missed the first three months with a fractured right ankle.