Baseball Evolution West: The New Coors Field?

Is Chase Field the new Coors Field? Is there a controversy? Some scandal? Allow us to start the rumors flying first. Our theory? BOB didn't like homers, but Chase is a huge fan.

Around this time in 2002, everyone was abuzz about the Great Humidor Scandal of Colorado.  It had been revealed that the Rockies kept their gameday balls in a humidity controlled chamber before use, thus making them less lively.  While Coors Field was still playing like a hitter’s park despite these efforts, for a few early weeks Coors was not the most extreme hitter’s park in baseball. 

Controversy ensued.  Was it legal for the Rockies to alter their balls in this way?  And even if it was, should it have been?  The controversy died down into apathy when as the season progressed, as Coors once again paced the majors in runs scored and home runs hit, both by significant margins.  It would go on to engender the most runs scored in baseball for two of the next three season, though never again would the park do so for home runs hit.

Right now, it’s safe to say that the Humidor has indeed slightly depressed home run totals at Coors, though not to the extent that the uproar of 2002 was justified.  But now in 2006, it appears that we may have learned our lesson too well.  Through the first six weeks of the season, Coors has actually played like a pitcher’s park, and we haven’t heard a peep from anybody about it.

Well, let the silence be broken.  Through Thursday’s games, Coors field ranked 21^st among ballparks in runs allowed and 23^rd in home runs hit (For those of you unfamiliar with park factors, this is determined my comparing the offensive output in a team’s home games to a team’s road games, so the quality of the pitchers/hitters that play in the ballpark doesn’t affect the calculation).  Specifically, runs in Coors have been depressed by 6.5% and home runs have been depressed by 17.5% versus the average of the other parks that the Rockies have played in so far, and all this during a season in which home runs are up 25% league-wide over the first 40 games.

I don’t know whether the lack of attention that this phenomenon is receiving is due to acknowledgement of the relatively small sample size or the lack of plausible theories.  Has Colorado suddenly sunk 1,000 feet in altitude?  Are they now employing a deluxe Humidor that turns baseballs into water balloons?  Probably not.  But if Coors continues to play like a pitcher’s park through the All-Star break, Major League Baseball had better launch an investigation to find out exactly what the heck is going on there.

While they’re at it, they might want to take a close look at Chase Field.  Right now, the Diamondbacks’ home stadium is playing to the hitters’ advantage more than Coors Field ever has.  This New Coors Field has thus far produced exactly twice as many triples as the stadiums in Arizona’s road games, and over twice as many home runs.  To put that in perspective, no other ballpark has increased home run output by even a factor of 1.5 in the early going.  As for runs scored, Chase Field has increased that stat by 34.5%, where just one other ballpark has increased run output by more than 20% (PNC – 22.8%).

Now Chase has always been a good hitter’s park because of the dry, warm desert air.  But why suddenly one of the best hitter’s parks ever?  It has been an unseasonably warm spring, but that has proven true across the country.  We’re cornered into silly speculation again.  Are the Diamondbacks using juiced balls?  Did they change something architecturally to produce a jet stream towards the outfield?  Is the ballpark suddenly atop a 1,000 foot sand dune? 

One factor that may actually be at play is the unbalanced early schedule.  By the end of the year, Colorado and Arizona will have played similar 162-game schedules.  But so far this season, the Diamondbacks may have played more road games in pitcher’s parks, or more road games against good pitchers, thus skewing their early park factors.  And the converse, of course, may be true for Colorado. 

But even if this skew has taken place, it’s hard to believe that Chase hasn’t become more of a hitter’s park and that Coors hasn’t become more of a pitcher’s park.  So Arizona fans should actually feel really good about their team’s 10^th ranked ERA of 4.38.  And Juan Cruz can explain away his nine runs allowed in less than one inning of work, chalking it up to an insanely unfair hitter’s park.

Now he just has to explain how it happened against San Diego’s lackluster offense.     

Read more from Keith Glab at www.baseballevolution.com.