Command PostMay 11, 2007
Location, Location, Location
By Joe P. Sheehan

The location of a pitch is one important factor in determining its fate. If a batter swings at a pitch thrown low in the strike zone, he has a good chance of hitting a ground ball, while if he swings at a higher pitch, there is a greater chance of him hitting the ball in the air. A difference in location of a couple of inches can be the difference between a home-run and a shattered bat. Pitchers need to be able to throw to precise locations and hitters need to be able to recognize if a ball is going to be hittable. As you can probably guess by now, this article is going to focus on the location of pitches, in and around the strike zone.

Before I continue writing though, I need to mention something. John Beamer wrote an really interesting article earlier this week about the accuracy of the Enhanced Gameday data. Based on his examination of Kevin Millwood, John found that the tracking systems were inconsistent across stadiums. However, the biggest problems that John found were regarding the release point and the ball as it left the pitcher's hand. The chart he showed of the strike zone showed no stadium-to-stadium bias, which bodes well for my current article. I think the differences with release points are caused by difficulties aligning the cameras the same at different stadiums without a consistent reference point, but home plate should serve as a good landmark in every stadium to align the cameras for the strike zone.

John looked at the spread of pitches and thought they were random enough not to worry too much about a stadium bias, but I can do a little checking too. Enhanced Gameday provides an x,y location, tracked by the camera system, of pitches as they cross the plate, as well as an x,y location entered by a human stringer. The stringer enters the location where he thinks the ball crossed the plate. Here's a plot of the X coordinate for the computer generated values vs. the human entered values.

xygraph.png

As you can see, it's a pretty good match overall. I'm not looking for a 100% match, and I don't totally trust human entry on this either, as it's pretty tough to actually tell where the pitch was when it crossed the plate, so I'm comfortable using the camera-tracked values in this case.

Getting back to the article, lets look at where right handed pitchers throw to right handed hitters. Of the 11,109 pitches I have from these confrontations, here is where they all ended up. The strike zone is the red box in the middle and the graph is from the catcher's perspective. The numbers in each grid are simply the number of pitches thrown in that region. I didn't convert these into percents because the raw numbers give a sense of the number of pitches I have for each split. The chart is cropped on the sides and the bottom to focus on pitches that were near the strike zone.

rhprhbcount.png

It's nice to see that most of the pitches are located in the strike zone. This seems obvious, but it serves as another quick check on the accuracy of the data. I liked the simplicity of this layout and some basic trends pop out right away. Right handed pitchers work away from right handed hitters, and when they work outside the strike zone, it's typically low and away. They throw below the strike zone more than they throw above it.

Digging a little deeper, the three regions just off the plate on both sides (three inside and three outside) are interesting. At each height, there were more pitches outside than inside, but as the height increases the number of inside pitches remains relatively constant and the amount of outside pitches decreases. I have no idea if this is an artifact or an actual pattern, so here's the same graph, but for left handed hitters.

rhplhbcount.png

For left handed hitters, pitchers again threw more pitches outside, and were more inclinded to throw pitches below the strike zone than above it. As the height increases with a left hander at the plate however, there is more of a chance of an outside pitch. Do these trends exist when left handed pitchers are on the mound? Here are the two charts for left handed pitchers, but there doesn't appear to be much of a continuation of the trend. The other trends about working outside and below the strike zone also don't seem as clear, if they exist at all.

lhprhbcount.png lhplhbcount.png

It's nice to know where pitchers threw the ball, but what actually happened to those pitches when they reached home? Focusing on right handed pitchers throwing to right handed hitters, here is a chart showing the percentages of pitches in each region that are swung at.

rhprhbswing.png

Right handed hitters swing at anything in the strike zone, except pitches down and away. Those pitches are strikes but hitters will swing at them only half the time, similar the frequently they chase pitches in regions abutting the strike zone. My guess is that right handed hitters as a group are unable to drive the low and away pitch, so they don't swing at it. They can afford to take the pitch if they don't have two strikes. However, right handed pitchers have figured out that right handed hitters don't frequently swing at that pitch and consequently throw to that region more than any other region. Hitters may not swing at pitches in that region because they feel they are balls, although of the 406 pitches not swung at in that region, 69% (282) were called strikes. When hitters put pitches from that region into play, they had a .298 batting average on balls in play, which surprisingly isn't the lowest BABIP for pitches in the strike zone. Perhaps low and away isn't a utopia for pitchers after all. If fewer than half of right handed hitters swing at a strike, the only hitters who do swing at that pitch must be confident they can get a hit out of it, resulting in the average BABIP.

One surprising item on this chart is that the BABIP for pitches right down the middle is not the highest. Three corners are all hot zones for right handed hitters as a group. One explanation for the lower than expected BABIP is if 70% of pitches down the middle are swung at, a lot of those swings will be taken by bad hitters, swinging because of the location, as opposed to the pitch low and away, where the only hitters who swing at it know they can hit it.

rhprhbbabip.png

The swing percentage and BABIP charts for left handed hitters facing right handed pitching are below. When left handed hitters face right handed pitchers, they think they can hit the pitch that is low and away, but despite swinging at it 59% of the time their BABIP is only .238. The location must be especially tempting for left handed hitters to get those results and continue swinging at it. Not surprisingly, right handed pitchers threw the second most number of pitches to that region. Lefties also appear to be vulnerable up and in, but right handed pitchers haven't targeted that area yet. Another interesting detail on the swing percentage charts is that despite a difference in the distribution of swings, both left handed hitters and right handed hitters swung at 63% of pitches in the strike zone.

rhplhbswing.png rhplhbbabip.png

Before I wrap up the article, I should mention that I do have the left handed pitching versions of the Swing Percentage and BABIP charts, but I don't have enough pitches in each region to draw any real conclusions from them, so I didn't include them. Even with the graphs I did use, I would feel more comfortable making the statements I made with a full season of data to back me up.

I learned a couple of interesting things while writing this article though. I had no idea how frequently batters swing at pitches in different areas of the strike zone. I knew roughly how much batters swung, but to actually see where they swing at pitches is pretty cool. With enough data, I would like to expand those charts, and do them for individual players. I would love to see what Vladimir Guerrero doesn't swing at or where someone like Scott Hatteberg swings. Are some pitchers able to consistently get batters to swing at pitches that aren't in the strike zone? I also learned that left handed and right handed hitters as a group have different holes in their plate coverage. Right handed pitchers as a group were able to exploit the aggressiveness of left handed hitters and throw pitches to an area where the batters couldn't hurt them. The pitchers were also able to exploit the passiveness of right handed hitters and throw pitches in an area of the strike zone where there was a smaller probability of the batter swinging. Maybe pitchers aren't as dumb as people think.

Comments

It is not surprising that BABIP is low for balls down the middle because more pitches go there than elsewhere, and fielders play for where pitches down the middle are likely to be hit. The upper and lower inside corners appear to have fewer pitches thrown there so maybe more of those get pulled down the line for hits. However, the fielders can't afford to cheat without opening holes for balls thrown down the middle, or without tipping the pitch location for pitchers that won't miss down the middle.

Good stuff.

I was very confused, however, with your use of the word "away." It seems that you meant by away, inside on left-handers and right-handers. Isn't that the opposite of "away"? When you said right-handed batters have trouble with the low and away pitch, it immediately struck me as wrong, but then from the chart it was apparent that you meant low and inside.

The graphs are from the catcher's perspective, which I think is counter-intuitive to most people

It is, of course, no surprise that most pitches are away. No RHP throws a breaking ball inside to an RHB on purpose (sometimes such pitches will back up over the plate by mistake, but it is *never* by design), so a very high percentage of breaking balls (80%? 90%?) will be outside. Fastballs or straight changes will be thrown in or away, and probably skew more toward away (55%? 60%?).

It would be interesting if this could be broken down by some kind of pitch type, based either on velocity or break.

At any rate, this is fantastic stuff, and I look forward to more discoveries.

"My guess is that right handed hitters as a group are unable to drive the low and away pitch, so they don't swing at it."

They don't swing at it because it is harder to judge. The low, outside pitch is the farthest away from their eyes, "good" players will be able to judge it's location correctly while "bad" ones will think it's outside for a ball.

Am I the only one that was amused by the 11% that are swinging at the high, inside pitch? Is that some sort of a self-defensive reflex?

Joe might want to wander over to fangraphs.com for the individual swing stats. I thought they had done something along those lines using color to depict contact frequency.

Great stuff Joe:


Perry Husband (hitting/pitching instuctor) has taken the MLB data and has broken this information down even further....so much so there are two books on the subject! He has been studying the effects of velocity, location, pitch sequencing in regards to what is more effective for a pitcher to throw. In his most recent newsletter (in regards to home run percentages) he came to a similar conclusion as you did...actually there is a lower percentage of home runs with balls thrown right down the middle as there are with balls thrown down and away....20% less chance in fact. It turns out that from the hitters perspective there is more time for the batter to recognize and to be able to get the bat on the ball in this location than anywhere else on the plate. (amongst other variables) Needless to say I don't have space here to address what he has written two books on, but for those who are interested his stuff can be found at effectivevelocity.com. It is encouraging to see that independent studies are coming to similar conclusions based on hard data and not someone thinks they know just because they have been hanging around the baseball field.

Guys, thanks for all the great comments so far...I've got a couple responses to them and a couple questions too.

gc...I don't know if I agree with your reason for the BABIP being lower for pitches down the middle, because I don't think fielders are positioned for where pitches down the middle are going to be hit. I remember reading stories of shortstops and second basemen getting the pitch signs from the catcher and positioning themselves and their outfielders accordingly. For for some reason Cal Ripken sticks in my mind as having done this. Teams also have bench coaches who can position fielders to take advantage of the way a hitter is being pitched to.

Blastings/Ms...would the charts be easier to read if they were reversed?

Black Hawk...I started to break it down by pitch type and result, to try and see how much location impacted results. According to this study, http://www.fangraphs.com/blogs/index.php/pitch-location-and-groundballs/#co,
last year on Fangraphs (which is initially what caused me to start thinking about creating this database) Brandon Webb is able to get a higher than average rate of groundballs even if his pitches were up in the strike zone. I started to look at Derek Lowe and see if he had the same pattern, but I didn't see anything yet based the 3-4 starts he's made.

thumble...Great catch. That makes a lot of sense, and while left handed hitters swing at the low and away pitch more frequently, it was still low relative to how much they swung at other pitches.

dg...That makes sense, to drive an outside pitch (hit it for a homer) you need to let the ball get further back on the plate, which give the hitter an extra split second to track the pitch. Thats pretty amazing that there is a 20% difference from those 2 areas.

Using the AAA gameday, human-input data I created pitch distribution charts for a select few pitchers and posted them here:
http://minorleagueball.com/story/2007/5/1/18590/84326
Like Joe I used the catcher's perspective because that's what I'm use to seeing on gameday. Whenever I get excited about it again, I'll split the charts between left and righthanded batters, an idea I swear I had before seeing this article.

I'd be more comfortable using the computer data than the human data, too. I have actually seen the computer put some bad locations (pitches off the plate, that were pretty clearly on the plate, but it's only a difference of 3 or so inches), but I've also seen some really lazy ML scorekeepers where they put strikes down the center and put balls just at the central location of the side the pitch missed the strike zone on. Also, AAA scorekeepers will barely put balls off the strike zone even if they are thrown in the dirt or nearly hit the batter, but all-in-all the AAA data seems accurate enough to paint a coherent picture.

I had no idea AAA used Gameday, thats really cool. I understand the problems with ML scorekeepers, but if the data are any good, it seems like you could get a reasonable idea of where minor leaguers pitch. It would be interesting to compare location in the minors vs. majors...maybe a certain location is more frequently thrown to in the minors.