The Humidor Effect On Baseballs at Coors Field: One Decade In Part 2 of 3 Article Series

Saturday, July. 14/2012

Since the Humidor room has been put into use at Coors Field, Team batting averages have dropped 8-10% and HRs have dropped 20-25% yearly.  The Rockies still have routinely finished in the top 7 in all offensive categories for every year since 2002.  This year, they lead MLB in every offensive category.

Chuck Booth (Lead Baseball Writer and @chuckbooth3024 on twitter)– In the first 10 years of Coors Field, or the Rockies existence for that matter, the baseballs were being belted out of the park at a historically record rate.  Some of this was due to the steroid era.  Most of it was arrived at by the dry air of Colorado.  The reason is simple, in dry air the ball travels further than in thin air, thus causing more frequent home runs.  Baseballs being stored in drier air become harder and therefore explode off of a bat when contacted.   After nearly a decade with inflated numbers at Coors Field for offense, a decision was made by baseball and the Colorado Rockies to start holding/storing the game baseballs  in a  room-sized Humidor-that was installed at the Park in order to keep them moist.  This was done so the baseballs will not carry as far when hit with impact.  Elevation would still play a role in the baseball games. Baseballs carry farther in the thinner air and especially when they are rising in trajectory. Remember that in Denver, you are nearly a mile above sea level already.  In fact, there are purple bleacher tickets that you can buy at Coors Field  that indicate where that mile marker is. 

The cause and effect is harder on pitchers, whose curveballs curve less with the thin air than at sea level-leading to fewer strikeouts and the result is less pitches to use in their arsenal.   So has the Humidor worked since being implemented before the start of the 2002 season?  The answer is yes.  The amount of HRs hit now sits with the rest of the MLB Parks that are amongst the top 10 over the last decade.  The averages have dropped only around 10% of what they were, however Colorado is routinely in the top 4 or 5 parks for average on a yearly basis in the MLB and dominate the NL in home average.  In 2012, the hotter temperatures(and dry air) have   helped  the team to lead every offensive category in the Major Leagues once again.  Now, there is still a decisive advantage to playing at Coors for hitters when it comes to playing an 81 game schedule there.  I am going to look at the careers of some previous players to show you the weighted advantage of having this park as a home venue.  We are going to look at the careers of Larry Walker, Todd Helton, Carlos Gonzalez and Garrett Atkins.  It is easier to use the hitters as a barometer when deciphering this study because not many pitchers ever prosper again in any city after playing for the Colorado Rockies. See: (Jeff Francis, Ubaldo Jimenez, Mike Hampton and Jason Jennings once they left Coors Field or before they arrived at Denver after playing somewhere else first.)

For Part 1 of the Article Series:  Carlos Gonzalez on the Trade Block? Buyer Beware!  click here .

For Part 3 of the Article Series:  The Coors Field Effect: Part 3 of A 3 Article Series click here.

No other Rockies player took advantage of the Pre-Humidor Days more than Larry Walker, who was a .381 career hitter at Coors Field compared with a .282 average for the rest of the MLB Parks combined.

Larry Walker

Career Avg: .313, HRs-383 RBI 1311, OBP.400,SLG.565, OPS .965

Coors Field Numbers:Avg.381, OBP.462, SLG .710 OPS 1.172

Larry Walker was still a good professional hitter at .282 for his career away from Coors.  These stats are going to be very troublesome for the Canadian to ever try and enter the Baseball Hall of Fame.  When the teams batting average hovered around .333 with a .550 Slugging Percentage for the years he played in Denver, it was tough for anyone to slump.  I believe Larry Walker will have to be content with making it into the Canadian Baseball Hall of Fame.

Todd Helton 

 Career Avg: .320, HRs 354, RBI 1342, OBP .419, SLG .545, OPS .964

 Coors Field: Avg .350,  HRs 216, RBI 813, OBP .447, SLG. 614, OPS 1.061

Road Numbers Career: Avg .289, HRSs 138, RBI 539, OBP .389, SLG .475, OPS .864

Todd Helton is a .290 hitter away from Coors Field for his career . He has 138 Road Homers compared to 216 at home.  His RBI totals have him with 529 on the road compared to 813 at home.  The ‘ToddFather’ has hit 263 doubles on the road and 303 at home.  His 4 full seasons without the Humidor even being in effect will hurt his chances at the Hall.  Like Walker, the voters will penalize him for these stats.  As a first baseman who will finish around 2500 hits, he may fall short of the criteria to enter Cooperstown.

Garrett Atkins

Lifetime Career Average: .285, OBP .350, SLG .449, OPS .799

Coors Field Numbers: Avg .327, OBP .385, SLG .507, OPS .892

Road Numbers Career: Avg .252, OBP .322, SLG .406, OPS .728

Garrett Atkins only lasted 44 games as a Baltimore Oriole.

Other Ex-Players such as Andres Galarraga hit .334 at Coors, .282 everywhere else, Vinny Castilla, .331/.251, Ellis Burks, .334/.282 all foraged great numbers from the pre-humidor era at Coors Field.

Ellis Burks was one of several good hitters that joined the Rockies and used the inflated offensive numbers to his advantage. He hit .344 with 40 HRs and 128 RBI in 1996, while leading the league in slugging (.639) and Runs with 142

 Team Averages ( Pre-Humidor) Overall MLB Rank/NL Rank


Rockies were an expansion team in 1993

1993-.306 1/1                                       1998-.325 1/1

1994-.300 2/1                                      1999-.325 1/1

1995-.316 1/1                                      2000-.334 1/1

 1996-.343 1/1                                       2001-.331  1/1

                                    1997-.321 1/1                   

The Rockies led the Major Leagues in batting at home 8 out of their 1st 9 years and every year in the National League.   From 1996-2001 the team hit .331.  The Humidor was installed prior to the 2002 season and the averages have dipped about 10%.


Team Averages (Post Humidor) Overall MLB Rank/NL Rank


 2002-.313 1/1                                       2007-.298 3/1

2003-.294 2/1                                      2008-.278 9/4

2004-.303 2/1                                      2009-.287 3/1

2005-.300 1/1                                       2010-.298 1/1

2006-.294 3/1                                       2011-.275 7/2

Currently in 2012   .291   1st/1st

The Rockies have lead the National League for home batting average in 8 out of the last 10 years, while finishing 1st overall in the MLB 3 different times.  That is great considering the pitchers hitting slot out of the 9th hole.  This year, the club leads all offensive categories in the MLB at home again.  If you take out the pitchers at bats from the lineup the averages raise about another .15 to .20 average points.  The positional players all hit for an average of about .315.  The Rockies positional players have led the MLB for all 20 years of the Rockies existence. 

That brings us to the column that our Lead Baseball Columnist (Jonathan Hacohen) wrote about Carlos Gonzalez.  I will not steal his thunder and you can view that article right here.  This is just a further illustration of the Coors Field effect on a players numbers and to always take this into consideration.  The Humidor has taken away the gawdy numbers that the pre-2002 Rockies displayed, yet that doesn’t change the fact it is still the #1 home ball park to hit in currently.  If you play 81 games there a year, your numbers will be heavily weighted.

Coors Field is a beautiful ballpark and is often ranked in the top 10 amongst extreme ballpark chasers.

 ***Thank you to our Lead Baseball Writer- Douglas “Chuck” Booth for preparing today’s feature on MLB reports.  To learn more about “The Fastest 30 Ballgames” and Chuck Booth, you can follow Chuck on Twitter (@ChuckBooth3024) and you can also follow Chuck’s website for his Guinness Book of World Record Bid to see all 30 MLB Park in 23 days click here  or on the 30 MLB Parks in 23 days GWR tracker at the Reports click here. To Purchase or read about “The Fastest 30 Ballgames Book, ” please click here ***

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About chuckbooth3023

I played competitive baseball until 18 years old and had offers to play NCAA Division 1 University Baseball at Liberty University. Post-concussion symptoms from previous football and baseball head injuries forced me to retire by age 19. After two nearly made World Record Attempts in 2008, I set a New World Record by visiting all 30 MLB Parks (from 1st to last pitch) in only 24 Calendar Days in the summer 0f 2009. In April of 2012, I established yet another new GWR by visiting all 30 Parks in only 23 Calendar Days! You can see the full schedule at the page of the . In 2015, I watched 224 MLB Games, spanning all 30 MLB Parks in 183 Days. Read about that World Record Journey at

Posted on July 14, 2012, in The Rest: Everything Baseball and tagged , , , , , , , , , , , , , , , , , , . Bookmark the permalink. 14 Comments.

  1. If the Rockies are being penalized for hitting at Coors field, why are pitchers not penalized for pitching in a pitcher’s park? Seems like a double standard that is extremely unfair to any Rockies player. People should look at stats regardless of where those stats were accrued. Each park has something that benefits certain players, it’s just something we have to accept in the day and age where each stadium is completely different than any other.

    • I always do. However, for this report by itself, you can’t ignore that the Rockies have led the NL 19 out of 20 years in MLB (by a wide margin) pre or post humidor. Their position players have averaged .20 pts higher than any other team. I am the first one to say things. Like the Seattle Mariners are hitting.200 at Safeco while .260 on the road. Or pitchers have a great advantage pitching at Safeco, Petco, McaFee Coliseum, AT@T Park. Or that hitters have a great time at The Ballpark in Arlington, Skydome or Fenway. This Park’s advantage is the ‘clubhouse’ leader out all of the home advantages by far.

    • Thank you for your comment Josh. We are adding it to this week’s edition of Ask the Reports:

  2. You might be interested in the article I wrote for Baseball Prospectus about the effect of the humidor on home run production at Coor (and the expected effect at Chase, should they decide to use one). See

    • Man, that is really scientific and I am sure we are both speaking along the same lines, just different verbiage. The Home Runs hit have significantly gone down the decade since they used the Humidor, The Averages have also dipped about 8-10%. However with the thin air and opposing pitchers not having as much spin on their baseballs, it still gives the advantage to the Rockies hitters. The Rockies pitchers however, are at the mercy of the Field. Also once a pitcher has left the Rockies, the rate of failure somewhere is completely enhanced. Other than Closer Huston Street, I can not recall a pitcher that has fared that well after leaving Denver. It will continue to be a hot- topic as far I am I concerned. The biggest thing people forget is that the pitchers hit in the NL so they should all be 10% less of a average hitting team than the AL clubs.

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