Home runs at Target Field

Maybe it's a bit early to write the tale of home runs at Target Field, but I've been having fun with the data from Hit Tracker, and I thought I'd share a bit.  All data is from hittrackeronline.com.

We all know that Target Field isn't giving up a lot of homers.  It's seeing 1.39 per game, good for 5th least in baseball, ahead of only PNC Park, Safeco Field, Citi Field, and McAfee Coliseum, all of which are home to fairly light-hitting teams.  So why are homers so hard to come by?

The cold? 

Well, according to Hit Tracker, temperature is taking off about 0.8 feet from the average Target Field home run distance compared to a "neutral" temperature of 70 degrees, which is the 5th most suppressive temperature effect in the majors (Safeco, McAfee, AT&T, and PETCO are 1-4).  So there's something there, but -0.8 feet is not a huge impact (average is -0.1).  It also hasn't been all that cold by Minnesota standards, so maybe in the years to come temperature will shut down the long ball to a larger extent. 

How about wind? 

Not, on average, a real big factor.  According to Hit Tracker, it's adding about 1.9 ft. per homer on average, which is very close to the MLB average (1.8).

Wind is a fickle thing though.  Take Michael Cuddyer's homer on April 15.  This ball traveled 346 ft. to the left-field corner, making it the shortest homer to date at Target Field.  It was also the highest, with an apex of 154 ft. (Target Field's second highest was 132 ft. and average is 84 ft.) and had the steepest angle off the bat: 44 degrees (with the second-steepest being 35.6 degrees and an average of 28.2).  According to Hit Tracker, the wind carried this homer 43 extra feet!  If it had been hit with no wind, on a 70 degree day, at sea level, Cuddyer's shot would have only traveled 298 ft.  The next-biggest wind assist was 15 extra feet, added on to a Corey Hart shot that went 440 ft. anyway.  If you take out Cuddyer's outlier of a home run, wind is adding only 1.1 feet on average to Target Field homers, which is below league-average.

So are players just not hitting the ball very hard off the bat? 

Well, Hit Tracker doesn't have data for non-homers, but homers at Target Field are hit with an initial velocity of 103 MPH, which is just a tiny tick below the average across baseball.  The average angle of elevation for homers at Target Field is also unexceptional.

So do you have to hit the ball especially far to homer in Target Field? 

Again, no.  In a way, it's quite the opposite.  The average homer at Target Field is going only 387 feet, which is 3rd-lowest in baseball.  And consider balls hit over 420 feet--balls that would be homers just about anywhere.  The average park has seen 11 homers going this far, while Target Field has seen only 3 such blasts (only Camden Yards and Safeco have seen fewer).  "Cheapies" on the other hand, are fairly common.  Almost half (48%) of Target Field's homers are under 380 ft.  Only Citizen's Bank, a real bandbox of a park, has a higher percentage (52).  The league-average is only 27%.  "Super-cheapies"--I'll call those under 360 feet--account for 12% of all Target Field homers.  Only five locales--Citizen's Bank, Minute Maid, Fenway, Comerica, and Yankee Stadium--have seen a higher percentage.

So what gives? 

By far the overriding character of Target Field seems to be that it's an extreme pull-hitters' park.  You can measure this with Hit Tracker data using the angle at which the ball leaves the bat.  Divide fair territory into four equal pizza slices.  The average ballpark this year has seen 19% of its homers initially hit in the left-field slice, 13% in the right-field slice, and 68% in the middle two slices.  By contrast, Target Field has seen only 48% of homers initially hit in the middle two portions, the lowest such figure by a good margin (2nd-lowest is 54%).  The Hit Tracker data is for where balls go right off the bat, so more balls will land in the outer quarters than are indicated by these percentages since, if not hit dead-on, balls will tend to slice toward foul territory.  Thus, the scatter chart of the landing spots is even more dramatic: http://www.hittrackeronline.com/detail.php?id=2010_756&type=ballpark

Clearly the center of the field is a massive dead zone for home runs.  Just as a comparison, here's Coors Field, which has about an average distribution of home-run balls (69% initially hit in the middle portions): http://www.hittrackeronline.com/detail.php?id=2010_1000&type=ballpark

Why don't balls go out of the middle of Target Field? 

I think a combination of distance to the fence, the height of the walls, temperature, and wind.  You can't measure these conditions perfectly with the data available at Hit Tracker, largely because it doesn't tell us anything about balls that didn't actually clear the fence, but with the data they do have, these seem like fair conclusions.  None of these conditions are strong outliers by themselves, but as a group, so far, the impact is unique in baseball.

This was all predicted with impressive accuracy by this series of articles from before the season: http://www.katron.org/articles/.  These articles feature deep U-shaped graphs suggesting much more difficulty hitting the ball out to center compared to the corners, especially in the colder months.  Check out the graph called "Target Field by Month Versus Metrodome": http://www.katron.org/articles/target-field/part-2.html This shows the percentage of simulated fly balls of various distances that went out of a simulated Target Field, accounting for likely temperature and wind conditions throughout the season.  The dead-zone in center is clear as day.  I'd speculate that far-right field is a bit easier to hit than indicated here, perhaps due to a wind-shielding effect by the stadium itself.  But overall, the data so far is almost a perfect match for katron's predictions. 

I love Target Field, but I don't especially love this aspect of it.  I don't mind so much that it suppresses home runs or runs-scoring in general, but why punish hitting the ball up the middle and reward shots down the lines, especially so much more so than anywhere else in baseball?  This seems especially ill-conceived when you have nearly $200 million wrapped up in a catcher whose power goes mostly to the center part of the ballpark.  Morneau is more of a pull hitter, but he spreads the ball around too, especially to right-center, which is the blackest part of the Target Field morass.

Here are park-by-park averages for 2010.  Maybe some of you will see something else interesting in the numbers: