Swing Potency: Part 1 | The Process Report

Swing Potency: Part 1

When trying to figure out a baseball player’s overall quality, one should look at one of the many, well tuned, well established metrics out there, such as wOBA. These established metrics do a wonderful job telling you how much a player has helped or hurt his team. They don’t, however, tell you very much about the player himself. For instance, Curtis Granderson and Matt Kemp both have fantastic wOBAs of .424 and .420 respectively this year, but they’ve achieved them in radically different ways. Granderson’s isolated power is a full .174 higher than Kemp’s. That’s enough clearance to fit the isolated powers of Jason Bartlett and Carl Crawford, with almost enough room for Jeter as well.

Though I watch a ton of baseball, and generally pay attention while I watch, I don’t by any means consider myself a qualified scout. That’s why I find it useful to break down a player’s more specific characteristics using statistics. Over the next few weeks, I plan on taking a close look at how the Rays players go about contributing value. I don’t promise that my articles will be predictive, or even particularly useful at determining total value, but I do hope that they’ll provide some new information about the batters we Rays fans think we know so well.

To start out, I’m going to take a look at the relationship between the power tool and the hit tool. I’ve often heard it said (though Jaime Cevallos, Zobrist’s sometimes swing doctor, would disagree) that swinging harder makes you more apt to swing and miss. If this is the case, players must make a tradeoff between swinging hard and swinging accurately. To see if this truism holds water, I plotted a graph of wOBAcon (a good measure of how effective a player is when he hits the ball) vs. Z-Contact% (the percent of the time a player hits the ball when he swings at a pitch in the zone) for all players with 500 PA from 2002-2011. I chose to use Z-Contact% rather than Contact% in an attempt to filter out the pitch recognition and patience skill and just look at the potency of a batter’s swing at a hittable ball.

Click to enlarge.

The plot yielded a not overwhelming but still significant r-squared of 0.27. Judging by these results, I think it’s reasonable to think of a player’s swing potency as a combination of his power tool (wOBAcon) and his hit tool (Z-Contact%). A player who falls above the line in this graph has a more potent than average swing, and a player who falls below the line a less potent than average one. Including Roy Oswalt and the rest of the low outliers (all of them pitchers I didn’t filter yet), the interesting dots are pretty much who you’d expect them to be. Barry Bonds and Albert Pujols generate amazing power for how controlled their swings are. Ryan Howard has an explosive swing, but with a good deal more holes in it. Mark Reynolds is near the best-fit line on one extreme, and Juan Pierre the other.

In part two, I’ll take a look at where each Ray falls on this swing potency continuum, and in part three I’ll try to investigate whether or not a player can alter his swing to move up and down the slope, and if he can, which Rays players should.

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  1. […] part one, I looked at the relationship between swinging hard and making contact. I graphed contact […]

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