Bratt has joined the Diamondbacks' taxi squad and is expected to be called up from Triple-A Reno to make his major-league debut Wednesday in St. Louis, Nick Piecoro of The Arizona Republic reports.
Bratt has logged a 2.84 ERA, 0.95 WHIP and 42:12 K:BB over 44.1 innings covering 11 starts this season with Reno. The left-hander recently returned from a brief stint on Reno's 7-day injured list due to a back injury and threw just 48 pitches over four frames in his most recent start last Wednesday, so he won't have a full workload at his disposal in St. Louis. Bratt is filling the rotation spot vacated by Michael Soroka (glute), and Bratt could receive at least one additional start beyond Wednesday while Soroka recovers.