It is widely known across baseball that Coors Field is the best hitter’s park in the bigs. Humidor or not, the mile high altitude, lets the ball fly off the bat, but what really makes the ballpark on Blake Street a hitter’s paradise? Many Rockies fans already know this, but people outside the Rocky Mountain region they don’t know why. Let’s let them in on our secret. No, it is not entirely the easy ability to hit homers that Coors allows. In fact, it is probably less about how the balls fly out of the yard than rather how the balls stay in the yard.
The fence in Denver is backed up, like really far back. If you take the five places the field size is measured (left foul-pole, left-center power-alley, dead-center, right-center power-alley, and right foul-pole) and average that number out, the Coors Field’s fence average distance from home plate is 375 feet. That ties Marlins Park in Miami for the longest average distance from home plate to the fence in the National League. Everyone knows that outfield is big, so much so that you could swim in it (awful pun intended). Marlins Park is a pitcher’s park and in theory it is true that a spacious outfield equal a pitcher’s park which is not the case at Coors. But the deep outfield seems to be overlooked at Coors, because everyone is caught up tracking home run balls or yelling about the humidor when they should be talking about the gigantic gaps that Coors features.
When building Coors, they compensated for the altitude by erecting fences further back. The Rockies know how big their outfield is, often starting two outfielders who are well equipped to play center-field, putting one in center-field and one in left-field. This can be seen with Carlos Gonzalez who is one of the best defensive corner outfielders. CarGo plays left field, because left field is so expansive. The power-alley is 390 feet from the plate. In addition, the right field line is the second furthest back in the NL. That right field fence stretches from 350 feet on the line (14 foot high wall) to 420 feet in deep right-center field. The right-field power-alley is a normal distance from the plate, but with the effect of the altitude, that area is where the ball gets out of the park the most often.
The Broncos would have no problem playing their home games at Coors with how wide-ranging the outfield is. In fact, before the humidor was put into play in 2002, there was talk among major league managers of playing four outfielders. This four-man outfield would have been used to defend against the extra 1.191 hits per game that Coors still allows compared to a neutral ballpark.
The question is: Which handedness does Coors Field favor? First some qualifiers. I took data from 2002-2014, since that’s when the humidor has been in use. Any other data is noted. Since there has been no other major league ballpark at a comparable altitude with enough of a sample size, (Mile High Stadium a year and a half of play due to 94 strike) some of these theories have no control to compare to, unless doing a heck of a lot of math where you factor altitude which at 5,280 feet makes a baseball roughly fly 9% further but that’s not the real deal.
Theoretically, what if someone built a pitcher’s park at altitude? Then we would really have a fun Coors debate, but I digress.
Now onto what you came here for. Since 2002, both leagues are hitting .290 at Coors Field: LHB .292 and RHB .289. The three points in disparity are far from the entire story. From 2002-2006, LHBs had a higher batting average in each year but one. The last three years, RHBs have had the advantage, while years in between the BAs alternated. The biggest difference in a single year was in 2013, when RHBs hit .299 and LHBs hit .265, a difference of 34 points. This explains why the Coors Field park factor for LHBs over the past few years has been completely underestimated. There are only two other times over the past 13 years when LHB’s BA has been under .282. Meaning either the past four years are outlier in a trend that is even or slightly favoring LHB, or a trend is beginning to build which favors RHB.
Coincidentally, this trend of LHB BA being lower than RHB BA coincides with the ending of Todd Helton’s career. In 2012 he took 9% of all at-bats from the left-handed sided of the plate at Coors Field. He also had 9% of all hits from the left side of the plate. Even going back to his prime in 2004, arguably Helton’s best year, he accounted for 14% of LHB hits at Coors and 12% of the ABs. So Todd Helton’s effect, or the effect one single hitter is not the reason for this trend.
Neither are league averages the reason, for the differences between LHB and RHB, which have stayed pretty consistent (not a 34 point difference between the split).
Could it be defensive? Interleague? Day and night games?
Defensive it is not. Carlos Gonzalez plays the most innings at Coors in LF and he has won three Gold Gloves (two in left).
Interleague it is not; there are not enough at-bats to make an impact of that magnitude.
Day and night games it is not. The Rockies have played roughly the same amount of day and night games in the past four years as they did in the previous nine.
BABIP (Batting Average on Balls In Play) is a factor. In years like 2012 with a huge disparity in the averages on each side of the plate, BABIP favors that side as well. However it is not entirely the reason for the shift in handiness advantage. In some years there is not a correlation between a higher BABIP on one side of the plate and a higher BA. Overall BABIP has a role in this “who done it” but I don’t see it as the lead suspect.
Going back to the dimensions of Coors Field, RHBs should have the advantage based on the left-center gap, but this would show throughout all years and not just the past few. It is kind of perplexing, honestly, how drastically the change has shifted in BAs from one side of the plate to the other. There is more to this, but I am not quite sure what the answer is. Is it the changing of weather patterns? Is it a dominance of either left-handed or right-handed pitching at Coors in recent years? Or is it just simply that there have been better players in some years on one side of the plate than the other?
Let’s explore the pitching idea. Much like the batting average trend, pitchers ERA favored RHPs more than LHPs from 2002-2010. Then the last four years, LHPs have had an ERA advantage. We are now seeing a definitive advantage for RHBs and LHPs. I cannot quite put my finger on the reason for the shift in these averages, although I have heard some wacky theories whether it be the batters eye has somehow changed or the newer buildings northwest of Coors Field are having an effect on the wind. Neither of those things I see to be true.
Now onto power.
Home runs are common at Coors Field. That’s the second most obvious statement ever. Right next to the moon is made out of barbecue spare ribs. But how common is the long ball for each side of the plate? Left-handed batters have a 3.48% chance to hit a dinger every time they dig in, while right-handed batters have a 3.36% chance per at-bat. It is the same for XBH (Extra Base Hits). Lefties have a 10.34% chance of an XBH per AB, while righties a 10.19% chance.
Once again, the past few years seem to be an outlier in an overall trend that favors LHBs. During the past four years, RHBs are .07% more likely to get an XBH than LHBs. This might not sound like a lot, but it is a .22% shift from the .15% advantage lefties have had over the past 13 years.
Home runs, however, have stayed at about a .10% advantage for lefties over the past four years. So this shift in handedness advantage has only been seen on balls hit into the field of play. As I stated earlier, RHB should have an advantage on balls in play if they are to pull the ball. The left-center gap is optimal for extra base hits. Once again this advantage would show across all 13 years of data and it is strange that it shows up three years in a row. This is now beyond the point of an outlier in my opinion, unless it is just one of those strange You Can’t Predict Baseball things that happen from time to time.
Coors Field is a hitter’s environment. The home run rate is well documented; the balls in play have not had the same coverage. The question of a left-handed or right-handed hitters advantage can be answered in two parts. One: Left handed hitters have had a slight advantage from 2002 until recently in terms of power and average. Two: The last few years the trend has shifted were right-handed hitters are now seeing a batting average advantage. If you had put me on the spot and said “which side of the plate at Coors Field has an advantage?” I believe the most suitable answer is neither side has a definitive advantage. Just don’t put me on the spot by asking why this shift has occurred.