Luis Castillo, Cincinnati Reds
Although the rest of his 2019 campaign doesn’t comparison to what he did throughout March/April, the Reds have a budding ace on their hands in Luis Castillo. His 9.9% walk rate is on track to be a career worst, but that’s paired with a 28.9% strikeout rate, which is on track to be a career high.
It’s worth noting that Castillo’s 4.0 fWAR has nearly doubled his 2018 performance (2.1) in about the same number of innings (169.2 in ’18, 178.2 in ’19). Although the young righty’s hard-hit rate allowed is up at 37.4%, the rest of his batted-ball profile looks like his solid rookie campaign of 2017.
Castillo has watched both his line-drive rate (21.8% to 17.8%) and fly-ball rate (32.4% to 26.9%) drop, while his ground-ball rate has shot back up (45.9% to 55.3%). Similar to Giolito, Castillo’s changeup has played a significant role in his success.
His fastball usage has gone down each of the last two years (62.4% to 57.2% to 50.5%) and his changeup usage has been on a steady rise (22.7% to 26.3% to 32.7%). Joey Lucchesi is the only qualified starter who has used his changeup more often than Castillo (35.3%).