Kershaw Curve vs Sale Slider
We’re back! After months of slogging through basketball and the World Cup we are finally able to hack on some baseball. This year we are focusing more on pitch selection, sequencing and effectiveness. For our analysis, we are using data primarily from Sportradar as well as various public sources to drive our overall data science pipeline using Google Cloud.
Some of the tooling has changed since we started in 2016, but the pipeline fundamentals remain the same — leaning heavily on Apache Beam and Cloud Dataflow for ETL, BigQuery for interactive analysis and feature development, and then iPython via Deep Learning images on Google Compute. No long running servers were harmed for this analysis — serverless+ephemeral infrastrastructure is the name of the game! Speaking of games… on to World Series Game One.
Red Sox vs Dodgers. East Coast vs West Coast. Beantown vs Hollywood. Two teams and towns that couldn’t possibly contrast one another more. Apropos the distance of 2,588 miles between Boston and Los Angeles marks the greatest length between World Series combatants in baseball history.
It’s hard to imagine a better opening World Series matchup than Clayton Kershaw (LAD) against Chris Sale (BOS) — the two best left-handed starters in baseball who will square off in game one of the Fall Classic. Today’s post focuses on what many consider to be two of the nastiest breaking pitches in the game: the Kershaw curve and the Sale slider. With the naked eye, both seem to defy laws of physics.
In Kershaw’s case, whether it’s his unconventional delivery, release point, ability to hide the ball, fastball setting up the pitch, and a number of other factors — his curveball always has opposing batters on their toes. This GIF is one of thousands available online. Spoiler alert: they’re all mesmerizing as this one:
The break on his curve seems unreal at times. So…exactly how much does it break…and how much in comparison to other breaking balls thrown throughout MLB? Among starting pitchers (min 200 batters faced), he has the most break of any left-handed pitcher. When factoring in all starting pitchers, Kershaw’s curveball sits in second position only to Mike Fiers (DET/OAK) who had more break.
Let’s dig into more here — Kershaw is 3 pitch machine: fastball, slider, curveball. Coming off his 2017 injury shortened season, Kershaw threw his curveball 16.5% of the time in 2018 (also injury shortened) but his average break length is back in shape.
Although Kershaw’s injury history the past two seasons are noted — an interesting look at all of his curves time aligned — there is a clear moment where his break changes. This passes the eye test when grouping by year
Another interesting note: 2018 is the most consistent with his curveball in terms of deviation.
Now that we’ve quantified the nasty break on Kershaw’s curve, what can we learn about the pitch in terms of result thrown both in and out of the strike zone? For this we binned each pitch into in zone and out of zone — relative to each batter’s strike zone and then calculated three bins outside of the strike zone.
- out_zone_2_swing_pct is percentage of balls swing on outside the strike zone within 3 to 6 inches.
- out_zone_2+_swing_pct is percentage of balls swing on outside the strike zone greater than 6 inches.
Batters swung on 42% of curves outside the strike zone and of those 35% were 6+ inches outside of the zone.
Net-net tonight keep an eye out of Kershaw’s frequency and execution of his curveball — and if/when it makes opposing hitter look silly.
Speaking of looking silly, Chris Sale has a slider that can break machine learning vision systems while buckling the knees of just about any professional hitter. Sale displays many of the same characteristics as Kershaw when it comes to his devastating slider (unconventional delivery, release point, ability to hide the ball, fastball setting up the pitch, and a number of other factors)
Sale is magical at getting hitters to chase out of the zone. When compared to Kershaw, he is evenly distributed in terms of getting batters to swing at bad pitches. Sale’s repertoire is different than Kershaw’s, but includes the devastating fastball/slider combo.
We’ll ask the same question about Sale’s slider. Exactly how much does it break…and how much in comparison to other sliders thrown throughout MLB? Among starting pitchers (min 200 batters faced), he has the most break of any left-handed pitcher. When factoring in all starting pitchers? Yep, still number one, regardless right or left-handed.
Now that we’ve quantified the nasty break on Sale’s slider, what can we learn about the pitch in terms of result thrown both in and out of the strike zone? Possessing the best breaking slider enables Sale to induce 44% of swings outside of the zone with 26% of those are 6+ inches outside of the strike zone.
We can only hope for an extended World Series and rematch opportunities between these two incredible southpaws. Enjoy the Fall Classic and look for more posts before each game!
