Missing most of 2019 due to injury, Castillo was very effective during his 2018 rookie campaign with his fastball leading the way in usage. Averaging 94.7 mph with just below-average movement, this pitch produced a .280 wOBA with a .317 BABIP. Its 20.4% O-Swing rate leaves room for improvement, even with its 10.9% SwStr rate.
Castillo’s slider showed positive results in 2018, hitting an 18.1% SwStr rate, a 50.4% zone rate, and a 37.1% O-Swing rate — just missing out on being a Money Pitch. This pitch featured elite movement on both axes at 83.3 mph, and led to just a 31 WRC+.
Castillo’s four-seamer tops out at 98 mph and was a solid pitch in 2018 with a .098 ISO against. His 53.6 Zone% and 10.9 SwStr% on his fastball combined with his slider to produce a promising rookie season for the Padres reliever.
Castillo threw his slider just under 50% of the time in 2018, and with great success, as the pitch produced an 18.1 SwStr% and a 50.4 Zone% out of the bullpen. He was effective against both righties and lefties and will depend on his slider going forward as a two-pitch pitcher.