Keller was promoted Wednesday from Double-A Altoona to Triple-A Indianapolis, Bill Brink of the Pittsburgh Post-Gazette reports.
After posting a 0.69 ERA and 0.81 WHIP in four June starts, the Pirates' top pitching prospect will be rewarded with a promotion to the highest level of the minors. While this may spark speculation that Keller could eventually reach the majors this season, the Pirates are a pretty conservative organization with such decisions, and there are plenty of other young arms who are close to big-league ready that the team probably wants to evaluate in this rebuilding year. Keller appears primed to make his big-league debut in early 2019. He finishes this season's run at Double-A with a 2.72 ERA, 1.12 WHIP and 76:32 K:BB in 86 innings.