Pittsburgh Pirates 2018: Data Visualizations


The Pittsburgh Pirates season has been over for a couple of weeks, and with the World Series starting on Tuesday, here’s a look back with some visualizations for the Pirates 2018 season.

Baseball Savant stores data that is collected through their series of Trackman radar systems that are installed at each Major League stadium.  The data is known as the StatCast data, with the tracking of spin rates, exit velocities, launch angles, etc.  Not all of the data is public, but with the data that is, you can visualize what happened in the season.

As great as numbers are, it’s just a data point with no meaning or context.  A ball breaking five inches glove side doesn’t put it into relation to useful context of other pitchers the pitcher threw.  The visualizations in this post will look at the location of pitches, the movement a pitcher has on their pitches, and histograms of player’s batted ball data using the tracked data from Baseball Savant.  All visualizations have a search tool in the filters that can be used to select the item you wish to see.

Where a pitcher throws his pitches is important, a sinker ball pitcher shouldn’t be throwing his pitches up in the zone, and being able to see where the pitches end up is useful.  The box formed by the lines resents the strike zone.  Using the filters, you can select what pitcher, the count, the batter’s handedness, and the pitch type of what was thrown:

Adding in pitch velocity shows (the table is in total, use the filter for the average velocity and spin rate by pitch type):

But location isn’t everything.  Visualization movement is helpful, and using the filters you can see how each pitcher’s pitches moved both vertically and horizontally, along with their average movement:

Comparing hitters, looking at their launch angle, exit velocities, and spray angles (estimated using this methodology with -45 being pulled down the line, 0 being dead center, and 45 being the opposite field line).  For comparing the distribution of the launch angle Pirates batters had:

But launch angles aren’t everything, and despite the Pirates ranking well in terms of “sweet spot”, it didn’t translate.  Hitting the ball hard matters, and is part of the difference between Josh Harrison and Corey Dickerson, even with their similar average launch angle.  Using this tool, you can compare distributions of all Pirates hitters:

And of course, where you hit the ball matters.  A right-handed hitter at PNC will have more power if he pulls the balls down the line closer to -45º than if he does if he pulls the ball at 30º because of the field dimensions.  For comparing each players spray angles all with the same base of -45 being pulled and 45 being opposite field:

Combining them to see each individual players distribution of batted ball events produces:

Seeing data visualized, especially with respect to a pitcher’s arsenal, is helpful when discussing players.  Distributions provide more than a raw average and show what a player was doing most often, as hitting to many groundballs and many pop outs might produce an ideal average launch angle, the batter didn’t actually produce it in a way you want.  These tools above can be filtered for the player, event, pitch type, etc and you can answer some questions about the Pirates 2018 season at a player level.

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