More than any other pitcher in 2012, Edinson Volquez captured why park effects matter. The Padres’ righty exhibited a similar profile at home and on the road — lots of strikeouts (8.9 K/9 home, 8.5 away), walks (5.0 BB/9 home, 5.4 BB/9 away) and ground balls (53 percent home, 48 percent away). All marks were slightly better at home, as expected, but there’s nothing in the basics to suggest a significant home/road split.
Except, of course, he pitched for San Diego. Volquez posted a 2.95 ERA behind just three home runs allowed (0.3 HR/9) at Petco Park but was ravaged on the road to the tune of a 5.60 ERA and 11 home runs allowed (1.2 HR/9).
The aggregate Volquez was a below average but still useful pitcher — he posted a 114 ERA- and 113 FIP-, numbers typical of a fourth or (more likely) fifth starter. A mediocre pitcher finding acehood within the Petco Park walls is nothing new, but it does raise a question: does the pitcher change his style to fit his surroundings when his home park is extreme?
Volquez is well suited to this exercise, as he throws both a four-seam fastball and a sinker and neither dominated the repertoire. Volquez threw 27 percent four-seamers against 23 percent sinkers in his 32 starts (PITCHf/x data from Brooks Baseball). A look at the home/road splits here shows a stark disparity:
Offspeed usage remained more or less the same, but Volquez’s fastball and sinker usage nearly swapped between home and road. He deployed the fastball well more than twice as often as the sinker at home, whereas the sinker saw nearly one-and-a-half times more action on the road.
Volquez and the Padres used an intuitive strategy. Petco Park rarely allows home runs on fly balls, which Volquez’s fastball drew nearly twice as often as his sinker (6.9 percent against 3.9 percent), and fly ball BABIP was still a tiny .173 even with the copious space Petco’s outfield provides. Therefore, stick with the fastball at home and bust out the sinker on the road to keep the fastball protected and the home runs limited.
In a way, the strategy worked. Beyond Volquez’s home effectiveness, his sinker was able to keep the ball on the ground on the road — he induced twice as many groundouts as flyouts and hitters managed just two home runs off his sinkers. But it was hit hard nonetheless — Volquez allowed 17 singles and 12 doubles out of the 95 sinkers put in play in road parks, good for a .337 average (.316 BABIP) and a .547 slugging percentage against.
When he did go to the fastball, it was utterly crushed. Not as many singles found their way through — just nine out of 64 put in play — but Volquez allowed five home runs and four doubles off fastballs on the road, or nearly one every seven times he threw the pitch. All-in-all, the pitch allowed a .281 average despite just a .219 BABIP — compared to a .318 mark off his fastball since 2007 — and a .578 slugging percentage.
Volquez is just one example, but he illustrates beautifully how far park effects can reach. The Padres developed a smart strategy to leverage his fastball — either his best pitch or his second best to the changeup, which needs to work off the fastball — at home but realized its flyballing ways would make relying on it away from Petco Park a risky proposition.
So not only did Petco Park impact Volquez’s results, but his tactics changed as well — something I think is often forgotten or ignored as translations are made between parks for those departing or entering San Diego (or, say, Colorado — Rockies pitchers will be worth a similar look). As with all baseball analysis, context is key, and the context of the park extends beyond just results.