RIP Jet Stream?

Jet Stream
With an influx of cash from three million fans pushing their way through the turnstiles the owners decided to give the 20-year-old Rangers Ballpark in Arlington (Globe Life Park) a face-lift and began with completely reconstructing the visitor’s bullpen.  Another change made before last season was building the Capital One Club behind home plate.  Many people began to speculate whether it would change the wind patterns inside the ballpark.  
The wind comes roaring in from the south during the summer and hits the northwest corner behind home plate.  Before the closed-in section of the stadium would turn the wind around and send it right back out towards right field.  This allowed seemingly routine pop flies become 380-foot home runs.  After the construction took place the area that trapped the wind was allowed to flow through and out the northwest side of the stadium.

As we all saw last year the pop wasn’t there in the lineup, but was it directly linked to the new project that the owners approved?  Let us dive into this issue a little bit and see what we find out.

First off we have to look at what happened to the club last year.  The ball club lost a power hitting left handed bat in Josh Hamilton and Mitch Moreland was not quite the same as what he was in 2012.  David Murphy was not too great, posting career lows in almost all statistical categories.

Josh Hamilton was a beast for the first half of the 2012 season (.308/.380/.635 with 27 HR’s).  He finished with 43 homeruns but his home or away splits are almost identical when you look at them.  Over his career with the Rangers his splits didn’t vary that much.  That leads you to believe that he was not affected that much by the gusting winds.

Let us turn to Mitch Moreland.  In 2012, Mitch’s home splits looked like this (.318/343/.553) while away form Arlington it looked a bit like this (.229/.299/.376). During 2012 Moreland hit 10 homeruns at home while hitting 5 on the road.  Then the construction was completed and his home/away slash looks quite a bit different at home (.221/.310/.394) while his away slash looks almost identical except his slugging went up 100 points.  His stats lead you to believe that the jet stream was killed during the off seasons before the 2013 year.

To get a broader prospective I went to look at the home run tracker over at ESPN and what I found is pretty astounding.    During the 2013 the Ballpark allowed 159 home runs.  In 2012 it was 202 home runs.  Since 2008 the average amount of home runs at the ballpark is 204.6.

In the scatterplot of the homeruns just from 2012 to the 2013 season it is astonishing to look at the difference in the balls that land in the right field porch.

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With all this evidence it would be safe to assume that the construction workers destroyed the jet stream at the ballpark, but I want to offer up something to ponder. This upcoming season this club gets a power left handed bat in Prince Fielder.  He will no doubt bring up the home run totals.  Moreland might have a bounce back year, and Jurickson Profar might shake things up as well. It will be interesting to see if the average over the next 7 years will be 50 long balls lower than what was previously set.  Only time will tell in this matter.
Matthew Ridenour

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