Baseball America named right-hander Mitch Keller the Pirates’ top prospect in the rankings it released Wednesday.
Keller, 21, reached Class AA Altoona in his fourth year in professional baseball. He had a 3.14 ERA in 77u2153 innings in high-A Bradenton before his promotion. Once reaching Class AA, Keller struck out 11.7 batters per nine innings with a 3.12 ERA in six starts.
Lower back tightness kept Keller out from mid-May to mid-June, and he made two rehab starts with short-season West Virginia before returning to Bradenton. He allowed two runs in 7u2153 innings with eight strikeouts in Game 3 of the Eastern League championship series, which clinched the title for Altoona, and threw a one-hit shutout against Bowie in the semifinals.