Ground Balls for Groundhog Day

Punxsutawney Phil is due to make his appearance today. He’ll survey the ground around him, take stock of the adoring fans, and prognosticate about the weather. With how bad our weatherpeople are at long-term meteorological predictions, maybe it makes sense for us to turn to a land-beaver for our winter forecast needs.

But what about the state of the ground in baseball today?

Since FanGraphs started tracking ground-ball rate in 2002, there haven’t ever more ground balls in the game. Home runs per game hit an eighteen-year low. ERA was at a twenty-year nadir. That’s it, six more weeks of winter for power hitters — our pitchers are learning how to get more ground balls and we’re in for some more offensive winter, right? Phil has seen his shadow and returned to his hole.

Wait, let’s do this again, says Bill Murray. Yes, ground-ball rate was at a ten-year high last year… by one-tenth of a percentage point. Here’s the relevant ten-year stretch:

G K/9 BB/9 HR/9 BABIP LOB% GB% HR/FB ERA
2002 17611 6.53 3.38 1.05 0.289 71.70% 43.30% 10.70% 4.28
2003 17817 6.4 3.3 1.08 0.291 71.20% 43.30% 11.20% 4.4
2004 18272 6.6 3.36 1.13 0.293 71.40% 44.20% 10.90% 4.46
2005 18035 6.38 3.17 1.04 0.292 71.70% 44.20% 10.60% 4.29
2006 18694 6.59 3.3 1.12 0.298 70.90% 43.70% 10.80% 4.53
2007 19294 6.67 3.33 1.03 0.299 70.70% 43.50% 9.60% 4.47
2008 19013 6.83 3.39 1.01 0.296 71.40% 43.90% 10.10% 4.32
2009 19097 6.99 3.46 1.05 0.295 71.90% 43.30% 10.10% 4.32
2010 18786 7.13 3.28 0.96 0.293 72.20% 44.30% 9.40% 4.08
2011 18754 7.13 3.11 0.94 0.291 72.50% 44.40% 9.70% 3.94

Allright, let’s just ignore the fact that ground balls have oscillated that one full percentage point over the last decade (and therefore a tenth of a percentage point is probably not a big deal) — hey, we ignore the fact that groundhogs have a three-to-six year life expectancy and we’ve been calling this one ‘hog “Phil” for decades. This shouldn’t be a problem. We’ve been ignoring Ned Ryerson for years.

Did anything *really* change last year?

It doesn’t seem like it. Pitchers did not throw more sinkers — the ratio of four-seamers to sinkers was 1.74 in both 2010 and 2011 according to Pitch F/x guru Harry Pavlidis. So no dice on pitching mix. How about pitch location in the zone? Thanks to Jeff Zimmerman, we have some knowledge. Look at the percentage of pitches that ended up flying high versus hitting kneecaps:

Whoo-hoo, that first step is a doozy. Case closed! Pitchers are pitching more in the bottom of the zone and that’s inducing more grounders and that’s why we had a Major League record in ground-balls last year. Phil would be proud of us. Six more weeks of winter for the sluggers!

Hold up. Hit the alarm and let’s do this again. Look at the numbers for the each zone, in half-foot increments:

2007 2008 2009 2010 2011
3.5 to 4 7.01% 6.87% 6.99% 6.56% 6.63%
3 to 3.5 15.09% 15.13% 15.15% 14.58% 14.50%
2.5 to 3 23.52% 23.62% 23.68% 23.28% 23.21%
2 to 2.5 25.26% 25.57% 25.34% 25.64% 25.54%
1.5 to 2 18.68% 18.74% 18.68% 19.31% 19.32%
1 to 1.5 9.68% 9.72% 9.82% 10.29% 10.46%

Yes, there might be a trend here. More ground balls — especially when combined with a ten-year low in BABIP — are good for the pitchers, and hence the nice 2011 ERA. But we shouldn’t expect this to continue, because the trend (if it’s there) is tiny. Putting too much stock in a seven-year sample in which the combined change in “high” versus “low” pitches might be two percent is like, well, asking an animal in Gobbler’s Knob about the weather in Philadelphia. If the trend does continue, though, we’ll have Punxsutawney Phil to blame, at least as much as pitch placement in the zone.

Happy Groundhog Day!



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With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.


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badenjr
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badenjr

How has the way the strike zone is called changed over this time? I sort of remember the the zone got tighter horizontally, but more low pitches were called for strikes. Is that true?

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