Taking Advantage of Petco Park

One of the concerns among Padres fans is the team’s apparent inability to hit at Petco Park since moving there at the start of the 2004 season. Suggestions on how to remedy this situation have included finding batters who aren’t intimidated by the park’s dimensions and reputation, moving the fences in to make the park more enticing to potential free-agent hitters, hiring a sports psychologist, and making sacrifices to Jobu.

During its first three years of existence, Petco Park has been an extreme pitchers’ park. We can verify this by checking the park factors for a few key offensive statistics over that time. Park factors give us a way to compare statistics compiled at home with those compiled on the road so that we can have a better idea of how each individual park plays relative to league average (which is represented as 1). In the tables below, anything higher than 1 favors the hitter, while anything below 1 favors the pitcher.

Runs Scored

An obvious first step, because it directly leads to winning games, is to look at runs scored.

Petco Park, Runs Scored: 2004-2006
Year Runs Rank
2004 .837 29
2005 .803 30
2006 .860 30

This is pretty straightforward. Since its inception, Petco Park has yielded fewer runs in all of Major League Baseball than any other park. For what it’s worth, its predecessor, Qualcomm Stadium, ranked #28 in this measure during its final season of baseball in 2003. In fact, here are the park factors for Qualcomm over its final three years:

Qualcomm Stadium, Runs Scored: 2001-2003
Year Runs Rank
2001 .819 25
2002 .835 24
2003 .825 28

Surprisingly, there isn’t much difference between the way Petco Park plays and the way Qualcomm Stadium played in terms of scoring runs. What has changed, especially over the past couple of seasons, is that the most extreme hitters’ parks have become less extreme, with more parks bunched toward the middle. Check out the progression of the run park factor leaders over the past six years:

Park Factor Leader, Runs Scored: 2001-2006

That’s a pretty severe downward trend. It’s also an indication that fewer extreme run-scoring environments exist now than did just a few years ago, which means that those still remaining, e.g., Petco Park, will appear even more extreme by comparison.

Before we get too comfortable with our assumptions, let’s run one more sanity check. We’ve already noted that the ceiling has fallen over the past six years. What about that phenomenon of bunching toward the middle? Here’s a look at the number of parks that have had a park factor for runs of between .9 and 1.1 (in other words, plus or minus 10%) over that period.

Percentage of Parks That Yield Runs to 
within 10% of MLB Average: 2001-2006

What we see is that over a span of six years, the number of parks that yield runs within 10% of league average has increased from just under half to just over three-quarters. So even though conditions in San Diego haven’t changed, the rest of Major League Baseball has, which has roughly the same effect as changing the conditions in San Diego.

This doesn’t solve our problem, but it helps us get a better grasp of what our problem is, at least in terms of scoring runs. How about other areas of offensive production?

Home Runs

Chicks dig the longball, and so, apparently, did batters at Petco Park in 2006—at least as compared to previous seasons:

Petco Park, Home Runs: 2004-2006
Year Home Runs Rank
2004 .691 30
2005 .750 30
2006 .982 16

During its first two years of existence, Petco was the single most difficult place to hit a home run in all of baseball. In 2006, it jumped all the way to the middle of the pack, to a level higher than had been seen during the Padres’ final seasons at Qualcomm Stadium. Many possible explanations for this phenomenon exist. Two of the more likely are:

  • buildings constructed beyond the outfield have changed wind patterns that may have kept more balls from leaving the yard;
  • pitchers have grown accustomed to the way Petco Park plays and are more susceptible to making mistakes high in the zone because they believe—consciously or otherwise—that they can get away with it

The fence in deep right-center field also was moved in about 10 feet prior to the start of the 2006 season, but it’s still a long way from home plate and not many batters (Carlos Delgado is the only guy I remember off the top of my head, and the charts I can find show that at most there were two others) hit the ball out to that part of the park anyway. The shift in dimension had a minimal impact on home runs, although I do believe it affected other areas, which we’ll touch on in a moment.


The park factor for hits has remained steady throughout Petco Park’s existence, so we’ll skip right over to another power measure, doubles. First, the park factors at Petco:

Petco Park, Doubles: 2004-2006
Year Doubles Rank
2004 .895 23
2005 .832 28
2006 .767 30

Next, the park factors at Qualcomm Stadium:

Qualcomm Stadium, Doubles: 2001-2003
Year Doubles Rank
2001 .750 28
2002 .769 26
2003 .876 23

These are close enough that they could belong to the same park. Looking back to the first table (2004-2006), there is an identifiable downward trend since moving to Petco Park. Why? Two conditions have changed during that time:

Visual evidence leads me to believe that Payton was a better defender in center than Roberts, and that Cameron was much better than both. Stats show Cameron and Payton to be similar, with Roberts significantly inferior. This doesn’t match with what the park factors tell us, so maybe we’re barking up the wrong tree here (or the defensive statistics aren’t trustworthy — but that’s a whole other can of worms).

How about the fence? Moving it in by 9 feet had the effect of shrinking the gap in right-center, which could help account for the fewer doubles. If this is the case, then we also should see a decrease in triples, which we do:

Petco Park, Triples: 2004-2006
Year Triples Rank
2004 1.519 5
2005 1.331 8
2006 1.086 13

The other big factor, I think, relates to the increase in home runs. With 167 home runs being hit out of Petco Park in 2006, as compared to just 118 a year earlier, it’s reasonable to expect that many of the balls that left the yard in 2006 had fallen just shy of the fence in 2005. This doesn’t explain everything, of course, as the gain in homers was 49 while the loss in doubles was just 23. Still, the increase in homers almost certainly played a part in the decrease in doubles (and also to triples, although those are more a function of speed and probably are affected more by the smaller gap in right center as well as the presence of Cameron in center).

In summary, then, doubles dropped at Petco Park in 2006 because more home runs were allowed there, the gap in right-center had been made smaller due to a shorter fence, and Cameron was a superior defender in center than Roberts had been in 2005.

Were the Padres Able to Use Any of This to Their Advantage?

You would think a simple question would have a simple answer. You would be wrong.

The Padres have been outscored at home in each of their first three seasons at Petco Park (they’ve also been outhomered at home, but that’s nothing new; the last time the Padres hit more balls out of their home park than the opposition came in 1998). There are two pieces of good news that accompany this fact. The first is that the run differential at home has narrowed since moving to Petco, which isn’t too surprising since the Padres overall are now fielding better teams than they were just a few years ago (or had your forgotten about Deivi Cruz and Wiki Gonzalez?).

The second piece of good news is a little harder to understand. Actually, it’s easy to understand; it just doesn’t make much sense. Despite being outscored at home in all three seasons at Petco Park, the Padres have posted a winning record in each of those seasons. Here’s the difference between their actual win total at home and expected win total, using the 1.83 exponent version of the Pythagorean wining percentage:

Padres Actual and Expected Wins at Petco Park, 2004-2006

Year RS RA ActW ExpW Dif
2004 329 342 42 39 +3
2005 308 318 46 39 +7
2006 315 337 43 38 +5

Maybe the Padres are using Petco Park to their advantage after all (or their strong bullpens are giving them the edge in close games). Or maybe they just made a sacrifice to Jobu. Either way, it’s difficult to argue with their success.

What will be most interesting to watch going forward are a) whether the gap between extreme environments at either end will continue to shrink or even hold steady and b) whether the Padres can continue to win at Petco Park despite continually being outscored there. The latter smells like a fluke, but stranger things have happened. An intriguing future study might be to look for other teams that have been able to outplay their Pythagorean record at home and, if any are found, see what shared characteristics might exist among them.

As for the compactification of extreme run-scoring environments in baseball, if this is a legitimate and sustainable phenomenon, it will have an impact on the way we evaluate players, especially as they move from team to team. It also will make any park (such as Petco Park so far) that continues to exist on the edge even more extreme in comparison to the rest of the pack, even if conditions don’t change one bit in that particular park.

References & Resources
Thanks to ESPN.com for the park factors and HitTracker.com for the home run locations.

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