Clarke was promoted to Triple-A Reno on Tuesday, Kyle Glaser of Baseball America reports.
The 24-year-old Clarke earns the call to the minors' highest level after rolling to a 2.91 ERA and 1.20 WHIP to go with 107 strikeouts in 111.1 innings with Double-A Jackson. The right-hander is one of the better arms in a Diamondbacks farm system lacking in high-end pitching talent, but despite finding success throughout his three seasons in the minors, he doesn't project as much more than a No. 4 or 5 starter once he reaches the big leagues.