In Corey Brock’s article on how Justin Upton was ready to contribute in the heart of the Padres order, Brock noted that Upton had compiled excellent stats at his new home park. In 192 plate appearances he has hit an excellent .291/.351/.541 with 22 extra base hits, 10 of which were homeruns. In the article Upton even goes so far as to say he enjoys playing at Petco saying:
“Everyone says it’s big, but I don’t think so, I think it plays pretty fair. I’ve enjoyed quite a bit of success here (Petco Park). I enjoy playing here. I think the park is great. I think it’s a great park.”
However, I believe this small sample size of plate appearances at Petco may not tell the whole story. So I decided to take a deeper look at his stats by first reviewing how many of the homerun’s Upton hit at Turner Field in 2014 would have been home runs in Petco based on length and secondly by adjusting Upton’s stats based on park factors. In 2014 Upton hit 29 homeruns, 18 of those homeruns were it at home.
After reviewing ESPN’s home run tracker I was able to determine of those 18 homeruns all of them would have been homeruns at Petco. This information helps to prove that Upton’s power will play well at Petco, however this may not be the whole story as there are other park factors other than fence distance that leave power hitters baffled in San Diego.
In order to determine how variables such as wind patterns and atmosphere affect power in different ball parks baseball statisticians have turned to park factors. Park factors allow us a way to determine which ball parks favor hitters and which parks favor pitchers additionally giving us a way to predict how a player would have performed in a different park.
A ball park’s park factor places a neutral field’s park factor at 100. So if the park factor is above 100 it is a batter friendly ball park and if it is below 100 it is a pitcher friendly ball park. Turner field has a park factor of 97 meaning it plays very close to neutral but gives the pitcher a very slight advantage.
Petco Park has a park factor of 82 which means it is an extreme pitchers park. With these numbers we can average out what Upton’s stats looked like last year and determine what it would look like if he played all of his games at Petco. If you are interested in the math behind determining these numbers you can look at this article on baseball reference.
So first let’s see what numbers Upton would have slashed playing at a neutral field and at Petco. After averaging his numbers I determined he would have a .266/.338/.488 batting line with 29 home runs. Fairly close to what he hit last year. However, if he would have played all his games at Petco he would have slashed .256/.325/.467 with 27 homeruns.
What we learn from this is that we should expect some regression from Upton in 2015, however as a Padres fan I am quite excited by those stats. How often have we dreamed of an outfielder with over 25 homeruns?
These stats agree with Upton’s assertion that he has no reason to fear Petco and I for one am overjoyed that he will be hitting homeruns at Petco in 2015.