Busch Stadium: Still a Pitcher’s Park

Good morning, Viva El Birdos!

You get a short article from me today because the issue that I had planned to write about ended up being no issue at all. That doesn’t mean that it’s not a little newsworthy, though.

That issue, as you can tell from the title, is Park Factors.

What are park factors?

Environment can have a huge impact on the way a baseball game is played. Altitude. Temperature. Humidity. Dimensions. Wind conditions. All of those things affect the way that pitches break and spin and balls travel off bats when struck.

Coors Field, a mile-high up in the Rockies, sees a higher rate of offense per struck ball than Petco Park on the coastline of San Diego.

It’s really easy to understand how this works.

If you take Nolan Arenado and give him 600 plate appearances in Colorado, he’ll produce some really massive offensive statistics. We know this. Because he did.

If you then take every single one of those 600 Nolan Arenado plate appearances – same pitcher, same pitches, same swings, same contact – and moved them down to the humid Mississippi air of Busch Stadium, the results would NOT be the same.

Some home runs would become outs. Some doubles would become singles. There might even be a few balls that work the other way, though. Some outs might just drop in because they don’t travel out to the outfielders.

Same everything. Different place. Different results.

Park factors are mathematical formulas that try to account for those differences that are relative to geographical context.

With thousands of plate appearances (over 6000 to be more precise) each season by both home and road teams inside of a ballpark, it’s possible to create ratios of how the same hitters perform in different places. Those ratios can be set on a scale of 100, with 100 being average, and even divided up by result – singles, doubles, triples, homers, walks, k’s, etc.

That’s what park factors are. Over 100, the ballpark makes offense “play up”. Under 100, the ballpark makes offense “play down.” Here’s what that all looks like at Baseball Savant, with their standard shading; red is high, blue is low.

Before we dig into these numbers, just a quick soap box. This is why I’m so bullish on weighted or adjusted stats, like wRC+, and why I use them throughout my articles. If you just look at a player’s OPS or batting average or homerun totals without considering where they played their games, you can get a warped idea of how productive or unproductive a player is.

We’re all too familiar with that conversation around here as both Matt Holliday and Nolan Arenado came to St. Louis from Colorado. The question for both players was not IF their numbers would drop playing at Busch but how much they would drop.

Nolan Arenado had the lowest homerun total of any full season of his career this year. He had his second-lowest ISO – Isolated Power.

He still produced by far the highest wRC+ of his career – 151 – and the highest fWAR total – 7.3.

Why? How do some of his worst career stats add up to the best season of his career? Park factors.

You can find the sortable data for the chart image above over at Baseball Savant. If you scroll down – scroll, scroll, keep scrolling, keeeeeeeeppppp sccrolllllinnng, almost there, nearly to the bottom – you’ll find the Cardinals coming in at 25^th place in park factors with a 97. Busch Stadium played about 3 percentage points below average this year.

That was almost news. For a good chunk of the season, that number was up above 100. Yes, for a time in 2022, Busch Stadium was playing as a hitter’s park. I wish I would have done a better job of documenting it, but outside of a few notes in articles and several references in comments, I didn’t do that.

I hit Baseball Savant yesterday morning fully expecting to write about how Busch’s park factor was changing and to offer a few theories as to why that might be.

Nope. Forget all of that. At some point in the last few months of the season – probably when I was lost in Albert Pujols la la land – the numbers flipped and Busch landed pretty close to where we all thought it would be.

Since the construction of Ballpark Village, Busch has played as a pitcher’s park. Here are park factors for Busch by season:

2018: 95
2019: 95
2020: 101 (only 1980 PAs)
2021: 92
2022: 97

Now, a 97 is much better than it was last year. 92 was particularly low. Surprisingly low considering that the humidor was put into use by the Cardinals for the 2021 season.

But, when it’s all said and done, there just isn’t a story here. The Cardinals have a very steady 5-point park factor range of 92-97, with 95 – their most frequent finish — sitting right in between. It’s a very clean statistical model, with one very small sample size outlier.

Takeaways?

One takeaway is not to read too much into small sample sizes. Like 2020. Or the early parts of 2022. In-season park factors simply aren’t all that useful. The smaller the sample size is, the more variance in the sample. It’s also possible that the websites that calculate park factor simply don’t adjust for league offense to establish the park factor until after the season is over. I really don’t know how it’s calculated. I do know that I won’t even bother checking park factors until after the season is concluded from now on.

A second takeaway is that there is some interesting information in the split stats. Busch Stadium had pretty hefty splits this season. Around here, we’ve talked often about how Busch “suppresses right-handed power”. That was certainly the truth in 2021, when Busch had a park factor of just 91 for righties and just a 74 for home runs by righties. That’s a VERY difficult environment to hit balls out.

It’s worth noting that things weren’t any easier for lefties. Their factor was a 93 overall, and a 78 for homers.

That changed last season. The overall park factor for right-handed batters jumped up to 101. Just above average. It was a 106 for homers. Well above average. Lefties? They had no chance. Their park factor was 89 overall and just 66 for homers.

How do we explain that? See the first takeaway again. Splits are just small sample sizes. There’s a lot of noise in them. And maybe a little bit of Albert Pujols.

Third and finally, the Cardinals’ strategy of buying low on pitchers who can get ground ball outs and keep the ball in the ballpark remains sound. The ballpark will still help those pitchers out. It’s just important for the Cardinals to remember that Busch isn’t selective in which offense it suppresses. If the ballpark helps our pitchers look good by suppressing offense, it’s doing the same thing for the other team. It’s a complete wash as half the innings pitched at Busch are pitched by the opposition. Still, guys like Miles Mikolas, Adam Wainwright, and Jordan Montgomery are going to be able to show shiny happy ERAs and a lot of that is due to Busch Stadium turning home runs into outs.

Park factors. An almost story that turned into a non-story that is just the same old story.

Have a great Wednesday, Viva El Birdos! I’ll be back on Friday with a podcast interview with Alec Burleson. Perfect for your listening pleasure during your holiday travels.