The Diamondbacks are expected to call up Diaz from Triple-A Reno to start Monday's game against Atlanta, Steve Gilbert of MLB.com reports.
Regarded as one of the top pitching prospects in Arizona's farm system, Diaz earned a promotion June 11 to Reno, where he's posted a 3.27 ERA and 1.23 WHIP alongside a 28:9 K:BB over 22 innings across four starts. Monday would mark the 23-year-old's MLB debut, though he would likely be sent back to Reno following his start against Atlanta.