The Orioles are changing the dimensions at Camden Yards. Here are some unproductive attempts at quantifying the impact.

I thought there might be a simple way to quantify what moving the fences at Camden Yards could mean for the Orioles. I was wrong.

Over his three-plus years leading the Orioles through their rebuild and trying to remake every aspect of baseball operations along the way, executive vice president and general manager Mike Elias has become pretty well-versed in laying out all the deficiencies he inherited and obstacles standing between the current state of affairs and October baseball at Camden Yards.

Nowhere in that long yarn was the ballpark itself, but it’s clear the Orioles viewed that as part of the issue with the reporting from my pat Nathan Ruiz of the Baltimore Sun this week that the left-field wall would be moved back as far as 30 feet and raised as much as five feet in order to keep the ball in the park more often.

Toss it into the bucket of pretty much everything else to do with this rebuild: it seems to make sense, and until it’s proven not to make a difference, it’s hard to argue that it won’t.

Inside the Orioles’ organization, there’s been plenty of research into this. They know the exact planned dimensions, where every ball hit landed over a long period of time, and what that would mean for the competitive environment of the ballpark for their pitchers and their hitters.

They employee an entire analytics department to forecast whatever difference it it could make, and also, hopefully, know the realities: that a deficient pitching staff that makes too many mistakes is punished with home runs for a reason, that the ball flies at Camden Yards in the summer heat anyway, and that the flag court in right field isn’t exactly hard to reach either.

But, because they’re doing it, and because there’s a lockout that’s sapping the game of anything else to talk about, it’s worth trying to dig into what it can mean as best as someone on the outside can. 

Nathan’s breakdown of which players would or wouldn’t benefit from it is a useful one, but it’s hard to know on a wider range without knowing the exact dimensions. From a team perspective, there are a few ways I thought to do so. They were fun to try, at least, but left me less sure of what it could mean than I was before.

Could xFIP replicate a more neutral ballpark?

One is using xFIP, which is expected fielding-independent pitching. In traditional FIP, what is essentially a pitcher’s ERA is calculated using only the things he can control: strikeouts, walks, and home runs. That removes the impact of fielders, and thus is viewed as a more true measure of pitchers’ skills. 

It’s advanced version, xFIP, calculates that same thing based on the league-average home run/fly ball rate instead of the one a pitcher actually allows. There’s nothing to indicate that some more playing field in left field will reduce the HR/FB rate at Camden Yards all the way to league-average, but showing the impact of what a reduced HR/FB rate did in theory for the Orioles is potentially meaningful.

The Orioles’ home numbers when viewed through this prism in 2021 paint a stark picture. (All ensuing stats via FanGraphs).

Only the Chicago Cubs’ HR/FB rate of 18.6 percent was higher at home than the Orioles’ 18 percent at Camden Yards, which undoubtedly contributed to their league-worst 6.00 ERA at home. 

Inserting the league-average HR/FB rate for 2021 of 13.6 into that equation paints a much different picture, with the Orioles’ staff at home posting a 4.77 xFIP. That’s still last in the league, but over a run’s difference per game could help a team that expects to have its offense improve in 2022 and stay on that trajectory for a while be more competitive quickly.

Over a five-year period preceding this change, though, the benefits aren’t as stark. From the beginning of the 2017 season on, the Orioles’ ERA over that five year span is 5.22, with an xFIP of 4.85. 

These same Orioles pitchers work on the road, too, and the difference in 2021 was half as wide by these two measures with the road ERA at 5.69 and road xFIP 5.05. However, over that same five-year period, the difference between their road ERA (5.48) and road xFIP (.491) is 20 points larger than the one at home.

There are other factors that go into xFIP, like strikeouts and walks, and the Orioles haven’t been proficient on the mound in either category over the last five years. Even considering all that, the difference in the rate of home runs they allowed per fly ball against the league average seems to be growing with time.

It’s also important to remember there are two different teams hitting and pitching each night at Camden Yards, both in the old circumstance and the new. Considering two hallmarks of the Orioles’ offense of late has been striking out and not walking, those two factors work in a pitchers’ favor in xFIP and thus negate whatever the high home run rate at Camden Yards could mean there.

The 2021 season had the highest difference in HR/FB rate against the league average since 2017 (16.4 percent for opposing pitchers at Camden Yards versus 13.6% league-wide), but opposing ERA at the park (4.23) was almost exactly the xFIP. Over the last five seasons, opposing pitchers had a 4.27 ERA against the Orioles and a 4.35 xFIP. 

This type of breakdown includes all the typical caveats, notably that not all home runs to Camden Yards go out to left field, and that opposing pitchers often have been better than the Orioles’ pitchers. Same goes with their hitters.

But the difference in expected results being so vast for the Orioles while being negligible for their opponents’ pitchers despite similar gulfs in HR/FB rate at Camden Yards suggests maybe the ball leaving the park is only a small piece of the puzzle.

On a batted-ball basis, what does expected slugging percentage tell us?

MLB’s Statcast data provided another avenue to explore what kind of difference moving the fences in left field out at Camden Yards could make, and it’s easier to group for the ballpark in this case, too.

According to BaseballSavant.com, in the seven seasons MLB has published Statcast data, the expected slugging percentage (based primarily on the exit velocity and launch angle of batted balls) at Camden Yards against Orioles pitchers has been meaningfully higher than the actual slugging percentage in five of those seasons. 

In 2021, it was a difference of 15 points (.641 actual against a .626 expected), but in 2015, 2018, and 2019, it was over 50. The seven-year total on aggregate is 31 points, with an actual slugging percentage allowed of .583 and an expected of .552.

Orioles hitters, again, haven’t enjoyed the same type of advantage over the expected results based on their friendly confines. Their delta in 2021 was actually 18 points, with an actual home slugging percentage of .596 and an expected of .578, but the seven-year average is 26 points. 

The ballpark’s 29-point difference in that period is ninth-highest in all of baseball, which is surprising, even as both expected slugging percentage and actual at Camden Yards are third-highest among full-time ballparks.

It stands to reason that pushing the fences back in left field could keep some home runs in the ballpark and also maybe add some gap doubles, so perhaps slugging percentages at the park could fall due to the new dimensions.

It was also noteworthy, using BaseballSavant.com data, that slugging percentages to left field all over the league were sky-high. That’s likely due to the proliferation of right-handed power hitters in the game, many of which are in the Orioles’ division.

The .704 slugging percentage to left at Camden Yards was in the bottom half of the league among full-time ballparks, as was the .584 expected slugging percentage to left. Seventeen ballparks had differences between the actual and expected slugging percentage to left higher than Camden Yards’ 124 in 2021, and that difference is about in line with the seven-year Statcast tracking period. So is where that rates among the league’s ballparks.

It’s important to note that the pending changes could be felt most starkly in the left-center field alley, and some of those balls from previous might be classified in this dataset as to center field as opposed to left.

There are much smarter people than I who could probably use public data to do a better job determining what the impact of the Orioles’ move could be, but until then, it’s all theory anyway. Who knows what kind of nonsense MLB will pull with the actual baseballs going forward, considering what they’ve already done? Can the offenses they face in this division actually get better, or could realignment compounded with this dimension change really make an impact?

The variables the Orioles can control outside of that, such as developing or otherwise employing better pitchers and having them make better pitches, are obviously challenging as well.

They wouldn’t be altering the park’s dimensions or wall size if they didn’t expect it to be a net benefit to them going forward. It’s just beyond me to quantify how quite yet, or possibly ever. This was a fun exercise, though.