Why new Yankee Stadium is HR-friendly

The Bronx Bombers are back in full force.

The Yankees have been hitting home runs at a record-setting pace at their new ballpark … and they'd have been on pace for more if they hadn't run up against Craig Stammen and the upstart Nationals during their most recent homestand. Through 35 games at the new Yankee Stadium, the Yankees have swatted 66 homers, putting them on pace for 153, four more than the record 149 hit by the 1996 Rockies at Coors Field. The Yankees and their opponents, meanwhile, have combined for 119 homers at Yankee Stadium, putting the park on pace for 250, the sixth-most hit at one ballpark in a single season in baseball history.

To think, if not for the Yankees and Nationals hitting a mere four home runs in their June 16-18 series, that full-season pace would swell to 291, only 12 behind the single-season record of 303 hit at Coors Field in 1999.

No wonder they call it "Coors Field East."

Perhaps you've heard the nickname; it has casually been tossed around in countless stories about the ballpark during the first three months of its inaugural season. Yankee Stadium's hitting-friendly confines have already earned it a comparison to baseball's all-time greatest hitters' park, and in the age of the humidor at Coors, it's actually a somewhat apt comparison.

Here's a breakdown of the per-game and ratio (batting average, on-base percentage, slugging percentage and OPS) numbers among new Yankee Stadium in 2009; Coors Field from 2005 to '09, the humidor-influenced period in that ballpark's history in which numbers have remained most consistent from year to year; the former Yankee Stadium from 2004 to '08; and this year's league average:

Now, here's a comparison of new Yankee Stadium in 2009 with both Coors from 2005 to '09 and the former Yankee Stadium from 2004 to '08, except with each category calculated using the same formula used to determine our Park Factor page. Naturally, the league average is unnecessary to list here, as a league-average ballpark factor, obviously, would be 1.000.

It's not at all hard to see how much of a homer haven this new ballpark is. Home run production is up 42.7 percent at new Yankee Stadium from its predecessor during the aforementioned time span, run production is up a healthy 7.8 percent. But the most shocking revelation is how much easier it is to hit a home run there than it has been at Coors since 2005, not to mention comparably facile to score a run.

All that leads one to wonder: If the outfield dimensions at new Yankee Stadium were supposed to replicate the dimensions at the former ballpark, how could it be that their numbers are so radically different?

Greg Rybarczyk of hittrackeronline.com has one answer: The outfield dimensions, despite what was advertised, are not identical to those at old Yankee Stadium. As you can see in the diagram to the right, there are subtle differences between the two stadiums, most evident in the part of the right-center-field wall taken up by the auxiliary scoreboard and a portion of the center-field fence mostly located slightly to the left of dead center. At one point in right-center, in fact, there is a point in the fence 9 feet shallower than at that same point at the old Yankee Stadium, a significant difference.

Measuring batted balls hit between the new and the old ballparks, however, demonstrates that's not the only reason for the offensive explosion. According to Rybarczyk, there have been 12 home runs hit at new Yankee Stadium that wouldn't have exited old Yankee Stadium. Surprisingly, though, there have been seven batted balls that weren't home runs at the new park that would have departed the old venue. That leaves the ballpark with a net gain of only five homers. (You can see the specifics of these in the charts at column's end.)

Folks, the difference in dimensions alone cannot explain this home run surge.

So what is it, then? Wind currents? The diminished foul territory? Poorer quality pitching? A whole new set of ghosts of Yankees seasons past influencing batted baseballs? Whatever the cause, this doesn't seem like the kind of thing a team can fix by shifting a wall by a couple of feet. Besides, to that point, I'd like to know how the Yankees plan to move the auxiliary scoreboard, as well as deal with the certain loss of prime outfield seating, if they do. Minor changes to those ends in future seasons are possible, but place me in the camp that believes the Yankees made their bed by building this ballpark to these dimensions, and now they'll lie in it.

In other words, new Yankee Stadium probably will go down as one of the better hitters' ballparks, both for this and future seasons. The extent to which it will favor hitters in the long haul is unknown, and would be impacted by future changes. To be fair, 35 games' worth of numbers is still a relatively small sample size. We'll have to revisit the topic come season's end, or if the team plans winter changes.

Some other factors to consider: Some of the ballpark's early returns could have been a result of the Yankees still getting their bearings at their new digs; the wind currents could be impacted by the upcoming demolition of the old Yankee Stadium (some remain unaware that it will indeed be razed to the ground); and the sweltering summer heat might keep the numbers there in check in future weeks.

To that latter point, the following chart breaks down Yankee Stadium's numbers by homestand, to give you a sense how that is indeed beginning to happen:

For now, though, continue to exploit Yankees hitters (as well as their opponents' hitters) at the new venue, while approaching scheduled starters there with a degree of caution, especially fly-ball pitchers. It's a clear advantage, every bit as much as at any other top-10 hitter-friendly venue; it's for that reason I added Yankee Stadium to my list of hitter-friendly ballparks in my weekly Fantasy Forecaster.

The following chart identifies which Yankees hitters gain the most significant home-field advantage, ranked by greatest home/road OPS differential (100 plate appearances or more):

It's numbers like that that have the Yankees on pace to boast a remarkable eight different hitters with 20 or more home runs, six with 25-plus and four with 30-plus. Johnny Damon, the only player to have had as many as two homers in the new park that wouldn't have been at the old, is on pace for a career-high 31.

Talk about Murderers' Row.

Yankee Stadium homers that would not have left the old park

Yankee Stadium non-homers that would have left the old park

Tristan H. Cockcroft is a fantasy baseball analyst for ESPN.com and a two-time champion of the League of Alternative Baseball Reality (LABR) experts league. You can e-mail him here.