On Pitching in Petco

I was re-reading my “The Need for a Front of the Rotation” post when the devil’s advocate part of my brain hit on a potential problem with my argument there.

“Won’t a pitcher projected to be a #3/#4 type guy be elevated to #2-esque numbers throwing half his games in pitcher-friendly Petco Park?”

It’s true that pitchers certainly get their numbers boosted. Chris Young, for example, has a 4.68 career xFIP, but just a 3.87 career ERA. Why? Because the extreme flyballer (28% GB career) has a .265 BABIP and 8.2 HR/FB% over his career, not from luck, but from the park he’s called home most of his career.

So Young, over his career, has been a #4 starter masquerading as a #2. Fine.

On an individual level, this makes sense. It’s given further weight by the fact that the Padres’ AAA team, Portland, plays in a hitter-friendly park in a hitter-friendly league, so coming to the NL West in the most pitcher-friendly park in the majors actually could negate much of the jump in talent level from AAA to MLB-level hitters.

So, it then follows that some average Triple-A pitchers could post decent numbers with the Padres, and we’ve seen that borne out in recent years by Josh Banks, Wade LeBlanc, Ryan Webb, and Cesar Ramos.

However, while that makes sense for individual pitchers, it breaks down on a team level.

Let’s say we rate every player on a scale from 1 to 10, where a team entirely of 5’s is likely to win 81 games. Put in a neutral park, an entire team of 5’s would put up exactly average numbers, but in Petco, the hitters would get worse and the pitchers better, to where the hitters would look like 4’s and the pitchers 6’s.

That changes the scale then. Yes, you can plug a 3 or 4-quality pitcher into Petco and get average results, but you’re not accounting for the fact that your “average” offense is actually below average because of the park. If the Padres are going to plug in below-average pitchers who look average due to the park, they’re going to need to have an equally above-average offense (which Petco would then depress to average) to be an average team.

So the moral of the story is not to look at these numbers in a vacuum. Don’t say “Well, this guy’s got a 4.00 ERA, thank God he’s at Petco, or he would be bad.” Say “This guy’s got a 4.00 ERA, which is substandard given his home environment.”

The numbers go two ways, not just one, after all.