Everyone knows how excellent the Indians’ pitching staff was in 2014. They finished second in the majors in FIP-, behind only the Washington Nationals and tied with the Detroit Tigers for the best in the American League. They also struck out 1450 batters, the most by a team in one season in MLB history. Corey Kluber and Carlos Carrasco were the most notable members of the starting rotation, with Kluber winning the Cy Young and leading MLB in FIP-based WAR and Carrasco flashed ace potential when he had the best ERA- and second best FIP- in the second half of any pitcher (min 60 IP).
Both pitchers used an impressive arsenal of pitches to defeat hitters, but two of those pitches stood out due to how much trouble hitters had with them. Here’s a warning: looking at metrics that measure the success of an individual pitch is always a tricky thing. For one, pitchers use pitches to set up other pitches, so sometimes they’ll have to put a ball in the middle of the plate (if they’re behind in the count), or waste a pitch out of the strike zone (if they have a batter 0-2 or 1-2). In addition, game theory dictates that if both the pitcher and the batter were behaving optimally, the pitcher would distribute their pitches so that each pitch would have equal value. If the pitcher did otherwise, they’d be incentivized to throw the “more valuable” pitch a higher percentage of the time, until all pitches had equal value! (I’ll redirect any questions about this concept to the great MGL).
That said, now that we have had Pitch f/x for a full eight seasons, its fun to see how an individual pitch compares to pitches in the past. Harry Pavlidis and Dan Brooks have done incredible work (which you can find at Brooks Baseball) to classify every pitch thrown by major league pitchers, and now anyone can see how effective each pitcher’s pitch is. One of the best ways to measure a pitch’s effectiveness is using Pitch Type Linear Weights. This lets you calculate the runs created by each pitch a pitcher throws based on how much it changed the run expectancy of the at bat.
That brings us to our main topic – how Carlos Carrasco and Corey Kluber threw the two best pitches in the Pitch F/x era. When you look at the lowest runs per 100 pitches by a pitcher who threw the pitch at least 300 times in a season with at least 60% of those pitches coming as a starter, Carrasco and Kluber’s sliders are number one and number two since 2007.
Let’s take a look at those two pitches by looking at how they threw them (velocity and movement), when the pitchers threw them (usage), who they threw them to (platoon split), where they threw them (location), and what happened when they threw them (results).