Who Made the Biggest Improvements vs. Pitch Types in 2018? October 12th, 2018, SIS Blog By MARK SIMON Which hitter made the biggest improvement against a pitch type from 2017 to 2018? The answer should be no surprise – it’s Christian Yelich, though it wasn’t one pitch type, it was two. In 2017, Yelich hit .149 and slugged .194 against curveballs. He had 10 hits, three for extra-bases and recorded 62 outs. This season, Yelich hit .370 and slugged .685 against curveballs. He doubled his hit total to 20, had eight extra-base hits, including four home runs, and recorded 33 outs. Yelich had a 649-point gain in OPS against curveballs (from .450 to 1.099), the highest of any hitter against any pitch type this season. Among those Yelich beat out for the top spot … himself. He had a 447-point improvement in OPS against changeups, going from .507 to .954. He had four extra-base hits on the 401 he saw in 2017. He upped that to 10 on 331 changeups in 2018. Biggest Improvement in OPS vs. Pitch Type2017 to 2018 (Top player listed for each type, min. 50 PA)Pitch TypePoints ImprovementChristian YelichCurveballs648Cory SpangenbergSliders518Christian YelichChangeups447Luke MaileFastballs446 So how does Clayton Kershaw get Yelich out in Game 1? He doesn’t have many options. Yelich didn’t make the overall list for sliders, but against sliders from left-handed pitchers, he fared well, going 14-for-46 (.304 batting average) with three doubles and three home runs. That was a vast improvement from 2017, when he went 3-for-35 against sliders from lefties. In other words, he made roughly the same number of outs from one year to the next, but added 11 hits to the ledger. Yelich had four hits against Kershaw, three vs. sliders, this season – the same number of hits he totaled on sliders from all left-handed pitchers in 2017. Given that Kershaw’s fastball took a dip in performance this season, that doesn’t give him many options with which to work. It’s rare that we’d say this about anyone going up against Kershaw, but it looks like Yelich will have the edge in this matchup. Thanks to BIS intern Spencer Harrison for his assistance.