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2017 statistics with Double-A Montgomery and Triple-A Durham: 71 2⁄3 IP, 2.76 ERA, 1.09 WHIP, 6.8 BB%, 30.6 K%
Except for a spot start in July last season, Castillo has been a reliever his entire professional career. He was already 20 when the Rays signed him in 2014, making him extraordinarily old for an international free agent. It cost just $64,000 to sign him, and that appears to be a bargain. His fastball has been recorded as high as 101 mph, and he has a good breaking ball to go along with it.