Park factors can take three to five years to even out. Bear that in mind with everything in this article, as it is simply an early read on the new ballpark in Philadelphia. Who wants to wait three to five years to explore the topic?
First, a real quick schedule disclaimer — the Phillies have played three road games in Pittsburgh, Florida, Montreal, St. Louis, Arizona and San Francisco, and four in Colorado. So our park factors are essentially a comparison of Citizen’s Bank Park to those parks, not necessarily a cross-section of the entire NL.
Using 2003 (2002 for Montreal because it is unpolluted with the 2003 games in San Juan), the non-Colorado parks had an average park factor of exactly 100 — the combined effect of the parks is essentially neutral. So we are getting a reasonable array of opponents, except for Colorado — we’ll deal with Coors Field a little later.
The ‘marginal’ home opponents (the Phillies have played four ‘home-and-home’ series) are all pretty good (72-57), the road opponents are not (55-71). Since the Phillies have faced better offenses at home, this may overstate the impact of a positive run factor — however they’ve also faced better pitching staffs, so this should be offset, I just thought it was worth pointing out.
The Phillies have scored and allowed a total of 196 runs in 20 games (9.8 r/g) in the new park. On the road in 22 games they’ve scored and allowed 203 (9.23 r/g). This elementary park factor shows the new park as a slight hitter’s park — a 106 park factor, with a 103 overall environment for Philly hitters/pitchers, after accounting for 1/2 the games being played on the road.
We can’t forget there are small sample illusions to deal with. The Phillies have played four of their road games in the thin air of Coors Field. 57 runs were scored in those games. The Phillies won’t be back to Coors this year, so while 18% of their road games include Coors today, by the end of the year that will be reduced to 5%. Coors is an extreme outlier, much moreso than any pitcher’s park, so an adjustment is in order.
Let’s take the other 18 Philly road games and weigh them 95%, and add in the Coors road games at 5%. This gives an 81-game projection of 682 runs in Philly road games vs. 794 in home games. The resulting park factor is 116 (108 for an overall environment to apply to raw RC or ERA).
In a recent column for The Sporting News, Ken Rosenthal mentions, “A total of 57 home runs were hit in the first 19 games at The Bank, matching the total in the first 19 games of the season at Coors.” This fails to account for how many home runs the Phillies have hit on the road — the Phillies have much more power than the Rockies, so it stands to reason their games would see more home runs, even if they were in equal parks. Just how strong is the home run factor at the “New Vet”?
The Phillies have hit/allowed 47 HR on the road (2.14/g); as mentioned, 57 have been hit at Citizen’s Bank Park (2.85/g). This yields a basic HR factor of 133, which is quite strong these days.
That doesn’t tell the whole story though, as we again have to adjust for the Coors Effect. 14 of the 47 road home runs were hit in four games at Coors Field. Giving those their proper weight, we project 155 HR in Phillie road games this season (as opposed to 173). The Phillies and their opponents are on pace to hit 231 home runs in the City of Brotherly Love this season. Citizen’s Bank Park is on pace for a 149 home run factor, which would be one of the strongest home run factors in the game.
How much of the 116 run factor is explained by the 149 home run factor? Phils’ games are on pace to have .69 runs per game more in Philadelphia this year, with .47 more home runs in those games. According to XRuns a home run is worth 1.44 runs. This means that on average, .47 home runs lead to .68 runs. So 98% of the Citizen’s Bank Park’s run factor deviance from an average park is a result of the additional home runs. Basically the park is playing average — outside of the increased home runs.
One other thing that jumps out from the data — the Phillies’ own hitters account for the entire home run tendency of the park. The Phillies are on pace to hit 146 home runs at home and just 70 on the road, despite facing better pitchers at home. Their pitchers are on pace to allow 85 at home and 85 on the road (hitters and pitchers both adjusted for Coors).
Again, the split is even more significant when you remember that they’ve faced tougher hitters at home thus far. Again, it’s early in the season, and the samples are small — the split in the effect should even out some as the season moves on. The best thing to do with the data right now is average it out and remember it’s a small sample. The Phillies do have a slightly above average ground-ball staff (1.29-1.33 ground balls for every fly ball, depending on the source).
What should all of this mean to Ed Wade? While it’s still way too early to tell anything for certain (I can’t stress that enough), should this pattern hold up, home run hitters become a premium in Philadelphia. If they have the chance to obtain two players of roughly equal quality but different ‘styles’, say a Sean Burroughs vs. an Aramis Ramirez, they should go with the home run hitter.
Likewise, Philadelphia should avoid pitchers prone to the dinger more than a normal team would. I suspect Larry Bowa’s pitchers will end up allowing significantly more home runs at home than on the road by the time the season is out. For example, Robin Roberts wouldn’t work out quite as well if he were pitching for the Phillies today. Not that either is on the market, but a Mariano Rivera would be more effective here than an Octavio Dotel. That wouldn’t be true in a place like the old Astrodome, for example. The Phillies should focus on ground-ball pitchers, when possible, if this early sample is indicative of the true environment.
Next week I’ll take a look at the early returns of Petco Park in San Diego.