New Parks & Dimensions Projection Adjustments: Home Runs

The smiles appear before the response.

Ask a few Orioles hitters for their immediate reactions to news that the club is moving in the left field wall, and their approval can be seen on their faces.

The above quote came from the Orioles caravan and got me thinking about how projections incorporate three new park changes.

I’ve seen the park changes referenced in articles and pods for reasons to fade or target certain players. I lean on projections and assume that they incorporate dimensions into account when they create their projections. If the changes are already accounted for, I don’t want to overrate affected players. After looking over various projections, most seem to take the changes into account, but some haven’t yet.

To start off, the three park changes this season will be:

• The Athletics moving from Oakland to West Sacramento with offense could only go at the new park. The Oakland Coliseum was one of the most pitcher-friendly parks in the league.
• The Rays needed to move to the Yankees Spring Training facility that is an exact dimension match to Yankees Stadium. The biggest change for left-handed hitters will be the short fence in right field.
• The Orioles moved their left-field fence in to try to make the park play more neutral. Right-handed hitters should be able to hit more home runs.

To see how projections dealt with the changes, I collected the home runs values from nine projections (five public, four behind paywalls) for the most affected players and adjusted them to 600 PA.

I reached out to the projection creators to see what they are doing. ZiPS and THE BAT X said they adjusted their projections for the changes. OOPYS adjusted for Tampa and West Sacramento and plans to for Baltimore. Steamer adjusted for West Sacramento but not for the other two but plans to soon. I have not heard back from Clay Davenport.

Baltimore

Here are the four right-handed hitters who should see their home runs go up because of Baltimore’s left field fence coming in.

The top two and bottom one projections deviate the most from the middle. It’s interesting to see the average for ZiPS and THE BAT X being the same. Both have admitted to making adjustments.

An average difference of six is quite a bit when adjusting for plate appearances. It is a little interesting that the public projections are all grouped together.

Tampa

For the Rays, I looked at some of their left-handed bats to determine the variation.

Besides a Paywall projection on the top end and Davenport on the low end, the projections are in a tight band. I’m guessing creators could use the dimensions for Yankee Stadium.

West Sacramento

And now it’s time to focus on the power hitters for the Athletics.

With this final sample, the Davenport and a paywall projection are near the bottom, and a paywall is near the top. Otherwise, the projections are similar.

Overall findings

I expected more variation but the only constant was the Davenport projections being on the low side, especially compared to the projections that were known to make adjustments.