We’re in Year Eight of major-league baseball in Denver, which means we’re
approaching a point when we should have enough data to start determining
what type of baseball, and what type of player, is best-suited to winning
at altitude. We’ve seen a few different ideas implemented so far, as the
Rockies have moved through flyball hitters with so-so OBPs to the current
media-friendly speed ‘n’ defense model.

This Notebook won’t be proffering a solution: that’s a long-term project
that we at Baseball Prospectus hope to attack in the next year. But
what I want to do here is point out just how dramatic an effect playing in
the high-altitude environment of Denver has on performance.

A personal pet peeve is that even after nearly a decade, this effect is
underestimated by many fans and much of the baseball media. References to
Enron Field as being almost as good a hitters’ park as Coors Field
dramatically understate the effect Denver has on run-scoring and the
elements thereof. Any discussion of the Rockies–or assembly of the
Rockies–has to start from this point.

As an example, let’s take a look at the NL West offenses, first by actual
runs, then by Clay Davenport’s
Equivalent Runs,
which adjusts for ballpark:

Team             Runs    Rank NL     Team             EqR    Rank NL

San Francisco 542 1st San Francisco 531 1st Colorado 533 3rd Los Angeles 458 2nd Los Angeles 474 7th San Diego 405 5th Arizona 457 9th Arizona 388 10th San Diego 439 11th Colorado 308 16th

The offense that appears to be the third-best in the league is actually
the league’s worst
. That kind of effect can’t be overstated. It just

It works the other way, too. Take a look at the division’s rotations, first
as measured by ERA, then by Michael Wolverton’s
Support-Neutral Winning Percentage.
SNPct. adjusts for both park and the work of relievers
following a starting pitcher:

Team            StERA    Rank NL     Team           SNPct.    Rank NL

Arizona 4.28 1st Arizona .571 1st Los Angeles 4.62 6th San Francisco .502 7th San Francisco 4.67 7th Los Angeles .485 11th San Diego 4.68 8th Colorado .483 13th Colorado 6.24 16th San Diego .429 16th

The Rockies’ rotation looks like the worst in the league until you account
for the environment. After adjustments, it’s just a bit below average and
comparable to the Dodgers’ starters.

We can use another Michael Wolverton metric,
Adjusted Runs Prevented,
to see just how the park distorts the performance of the Rockies’ bullpen:

Team            RlERA    Rank NL     Team             ARP    Rank NL

Arizona 4.17 3rd Colorado 37.9 1st Los Angeles 4.20 4th Arizona 18.7 2nd Colorado 4.46 8th Los Angeles 4.1 6th San Diego 4.54 9th San Francisco -11.3 10th San Francisco 5.15 13th San Diego -33.4 15th

The Rockies have the best bullpen in the National League, despite an ERA
right around the league average for relievers.

According to Clay Davenport’s calculations, games in Denver in 2000 have
featured 38% more run scoring than games at an average park. The next-best
environment for increasing offense? The Ballpark in Arlington, at about
16%. Not only is Denver the highest-offense environment in baseball, but
that environment has more than twice the impact of the next-most
extreme one.

Denver is completely off any known scale of park effects. Any evaluation of
the Rockies, individually or as a team, has to take that into
consideration. Not just pay lip service to the idea, but completely accept
that everything has to go through the filter.


  • The Diamondbacks may finally have given up on Travis Lee, who hasn’t
    hit a lick since the summer of 1998. With Erubiel Durazo playing
    better as a first baseman and the D’backs likely to bring in a hitter to
    play right field, it’s probably best for all parties if the team tries to
    deal Lee. Lee is still an excellent first baseman and played a good right
    field this year; there’s no reason to believe he can’t get his career back
    on track in a different environment.

Joe Sheehan can be reached at

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