Doyle yielded two runs and fanned a career-high eight batters over five innings in a start with Double-A Springfield on Saturday.
The Cardinals have had Doyle expand his repertoire this season, per Derrick Goold of the St. Louis Post-Dispatch. That's led to inconsistency, with Doyle permitting 14 runs (12 earned) over 11.2 innings covering his first four outings. However, the hard-throwing southpaw looks to have found his rhythm the last two times out, allowing a combined three runs with a 13:1 K:BB over 9 1/3 frames.