Last week I wrote about the Nationals’ starting pitchers and what factors could be behind their differing batting averages on balls in play allowed. One of the factors I looked into was pulled fly ball percentage. As Mike Fast wrote for The Hardball Times in 2009, batters hit significantly better when pulling the ball than when hitting the ball to center or the opposite field. Fast used MLB Gameday data from 2007 and 2008 to find the batting average on contact, BACON, and slugging percentage on contact, SLGCON, on fly balls to the pull, center and opposite fields. His results are below.
| BACON | SLGCON | |
| Pull | 0.452 | 1.467 |
| Center | 0.217 | 0.498 |
| Opposite | 0.182 | 0.378 |
So with this in mind I began to think about other Nationals players who possibly benefited from pulling the ball more and the first player I thought of, as those who read the title of this post can probably guess, was Ian Desmond. Desmond was awful in his first two seasons in the big leagues before having a breakout year in 2012 where he swatted more home runs, 25, than he did in his first two years and change combined. And in 2013 and 2014 the power didn’t let up as Desmond belted another 20 and 24 home runs, quite a surge of power that seemingly came out of nowhere.
And now I had a possible idea as to the somewhere from whence this power came. So using Baseball Savant’s PITCHF/x search tool I looked up the number of fly balls Desmond hit to the pull, center and opposite fields each year from 2010 to 2014 as well as his BACON and SLGCON on those fly balls. The results were intriguing on a number of levels that I’ll detail soon. To begin with though, let’s take a look at Desmond’s pull percentage over the past five seasons.
So Desmond really did see a sharp uptick in his pull percentage from 2010-11 to 2012-13. This jives with what we heard from Nationals coaches and front office folks about Desmond’s new hitting approach in 2012. In Patrick Reddington’s 2012 season review of Ian Desmond at Federal Baseball, he tackled the sudden power stroke Desmond demonstrated. The most telling quote in that story came from former manager Davey Johnson who is oft credited with being the Desmond whisperer.
“I don’t know, for whatever reason when I got here [Desmond] was kind of trying to serve the ball to right field, let the ball get deep and kind of flare these little hits into right,” Johnson said. “He’d occasionally get some hits, but I remembered him as hitting the ball where it’s pitched. The ball’s inside, you get it out front, the ball’s away you go the other way and kind of drop that head in there.”
So the Nats tried to get Desmond to pull the ball more and he did and saw his overall power numbers skyrocket. While this seems to be solid evidence, we can get an even better picture by breaking down his performance by his fly balls to the pull, center and opposite fields.
| Pull | Center | Opposite | ||||||
| BACON | SLGCON | BACON | SLGCON | BACON | SLGCON | |||
| 2014 | 0.538 | 2.154 | 0.222 | 0.778 | 0.121 | 0.242 | ||
| 2013 | 0.571 | 2.179 | 0.269 | 0.654 | 0.093 | 0.116 | ||
| 2012 | 0.435 | 1.696 | 0.273 | 0.795 | 0.265 | 0.765 | ||
| 2011 | 0.316 | 1.053 | 0.205 | 0.359 | 0.089 | 0.089 | ||
| 2010 | 0.625 | 1.938 | 0.152 | 0.391 | 0.212 | 0.394 |
It seems the breakout in 2012 wasn’t just due to Desmond’s increase in pull percentage as he put up great number across the board, highlighted by an impressive .765 SLGCON on fly balls to the opposite field. As expected, Desmond’s opposite field numbers fell back to normal in 2013 and 2014, but unexpectedly he kept the power gains to center field. Combined with consistently good pull field numbers, outside of his miserable 2011, we can see exactly how Desmond made the leap into the power hitter he is today.
That does come with some concerns though. As you probably noticed in that graph, this year Desmond’s pull percentage took a dive back to his 2010-11 numbers. His center field power numbers were able to prop up his overall production, but as Fast found a player shouldn’t rely on being able to put up big numbers on fly balls to center field. A similar problem manifests itself in Desmond’s ground ball and fly ball percentages.
| Year | Fly ball % | Ground ball % |
| 2014 | 32.1 | 50.1 |
| 2013 | 34.1 | 43.4 |
| 2012 | 34.5 | 47.6 |
| 2011 | 30.5 | 51.9 |
| 2010 | 31.6 | 52.7 |
Just like with his pull fly ball percentage, Desmond saw a noticeable increase in his overall fly ball percentage and decrease in his ground ball percentage in 2012-13 compared to 2010-11, before seeing it drop back down in 2014. Desmond also saw his infield fly ball percentage jump from a career average of 8.6 percent entering 2014, to 12.9 percent this year.
For someone who built a large portion of his offensive and overall value on power hitting, these are not encouraging signs. Granted Desmond did still slug 24 home runs and his isolated slugging of .175 was right in line with his 2013 mark of .173. And the concerning numbers are coming from a one year sample size. It is absolutely possible that Desmond gets back to his 2012-13 standard again in 2015, but that doesn’t appear to be the likely outcome. With Desmond entering his final year with the Nationals before becoming a free agent these are the sorts of numbers that should give the Nats caution before deciding to break the bank on an extension for the star shortstop.
Citizens of Natstown 