The St. Louis Cardinals drafted Keith Butler in the 24th round of the 2009 amateur draft. The 6-foot righthander attended Wabash College in Mount Carmel, Illinois. Unlike many pitchers who eventually make it to a major-league bullpen, Butler has never started a baseball game in his professional career.
In the rookie leagues of Florida and Appalachia, at the age of 20, Butler made 23 relief appearances; in 30 1/3 innings, he struck out 38, walked 13, and hit four batters. Butler's ERA was 2.08, which lined up rather closely with his FIP (2.49 in the Gulf Coast League and 0.70 in 2 IP for Johnson City).
In 2010, Butler had a solid season in Batavia's bullpen. The righty made 27 appearances and tallied 50 K's to 15 unintentional walks in his 30 2/3 innings. Butler posted a 2.93 ERA and 1.93 FIP.
Butler pitched in Davenport (Low-A) and Palm Beach (High-A) in 2011, experiencing success at each stop. 22 years old, Butler totaled 15 1/3 innings in the Midwest League and struck out 16 opposing batsmen while issuing five bases on balls. He posted a 1.17 ERA and 2.09 FIP.
At Palm Beach, Butler made 34 appearances and pitched 36 innings. The righthander notched 52 strikeouts and allowed 18 opposing hitters to walk. He finished his stop in Palm Beach with a 1.25 ERA and 2.34 FIP.
Last season, Butler was a Springfield Cardinal. Pitching in the hitter's haven that is the Texas League, he made 53 appearances in relief that spanned 58 2/3 innings. His 2.76 ERA somewhat masked a 3.58 FIP that was fed by the highest HR/9 of his career (0.77), lowest strikeout rate (23.8%), and second-lowest walk rate (9.3%).
The Cardinals assigned Butler to Springfield at the outset of 2013. In 13 2/3 innings, he eviscerated opposing batsmen. Butler struck out 41.2% of the hitters he faced while walking just 3.9%. Correspondingly, his ERA was 0.66 and his FIP was 1.52. The Cardinals rewarded his hot start by promoting him to Triple-A, where he has thrown a mere 5 2/3 innings with a 9.53 ERA and 6.20 FIP.