Making some sense of the new Kauffman Stadium dimensions

Yesterday, the Kansas City Royals announced their most intriguing move of the offseason—one that involved zero free agent dollars, internal hirings or firings, or any discussions with other Major League Baseball teams. No, this intriguing memo simply stated that the Royals are moving in the Kauffman Stadium fences. It’s already done, and it’ll be ready for Opening Day 2026.

The Royals posted a handy graphic showing the new dimensions. Center field will remain untouched, but the biggest changes will be to deep left and deep center field, where they will go from a whopping 389 square feet down to 379 square feet. Shorter walls have also been installed throughout.

This isn’t the first time MLB teams have tweaked the dimensions of their parks. Just last year, the Baltimore Orioles moved in their fences after moving them out three years earlier. The rulebook is pretty lenient when it comes to stadium dimensions; as long as the distance to the foul pole is greater than 325 feet and the distance to center field is at least 400 feet, teams can pretty much do whatever they want (up to and including putting a hill in the outfield for funsies).

But just because teams have lots of wiggle room and can technically change the dimensions of their stadium every year doesn’t mean that they do so. Teams make changes only when it makes sense, usually to rectify a previous weird/wrong/bizarre decision or to give them a competitive advantage.

So why would the Royals change Kauffman Stadium’s dimensions? In the Royals’ case, it seems to be a little of column A, a little of column B.

The median playing field area in an MLB park is about 108,000 square feet, and 28 MLB stadiums’ playing areas are within 5,000 square feet of that number. Coors Field, whose altitude demands a big outfield lest every fly ball zoom over the fences in the thin mountain air, is one of those outliers at 116,729 feet. Kauffman Stadium, firmly squatting less than a thousand feet above sea level, is the other at 115,737 square feet.

That expansive outfield grass and lengthy distance to the outfield walls mean that Kauffman Stadium is a hellish place to try and hit home runs. Statcast’s park factors have Kauffman Stadium as the third-most difficult place to hit home runs in the league, where 15% fewer home runs are hit compared to a neutral park.

We don’t know what will happen exactly if the Royals bring in the fences. But we do know that it will be objectively easier to hit home runs in the new Kauffman. First baseman Vinnie Pasquantino shared on Twitter that he got 70 text messages within 20 minutes of the news dropping. He also shared this, which I have lightly edited for some grammar and ease of reading:

I’m very curious how this is going to play out in multiple ways. And honestly mostly from a data perspective (this hits close to home because I’m about to go into a room and hear how awful I am). The K was the 6th most hitter friendly ballpark according to the [Statcast] park factor[s]. Will moving the fences in make this better or worse? Hitters like hitting at the K because the visuals are nice, but everyone also agrees it’s been a pitcher’s park forever. What this means is that you can’t hit cheap homers. That’s literally all a hitter saying a park is a hitter’s park or not means. But the data firmly supports it being a hitters paradise because you can get more singles, doubles, and triples. Will the park factor actually go down if it’s more of a neutral park because there will be less triples even if there is an uptick in home runs? What will this mean for WRC+? We get punished with this stat for playing at the K now.

So what will happen? More home runs = more runs produced, but if the park factor goes down so does the punishment for probably the most important stat in our game from an individual standpoint [wRC+]. All in all, I truly believe hitters/pitchers alike just want fairness, but we play one of the only sports where the field size changes and I think that’s one of the cooler things about our game. I just rambled a lot but I think it’s cool the Royals were willing to make these changes to make it more of a neutral ballpark.

Vinnie makes a couple of observations here that I think are very interesting, and align with the conversation I had with him about hitting back in August. One, that parks don’t affect all hits equally. It’s comparatively easy to hit doubles and triples in Kauffman Stadium, for instance, because it’s such a big place. Is the tradeoff going to be worth it?

For Vinnie, probably. It’s hard to be sure, but looking at Vinnie’s spray chart at Kauffman Stadium for outs and doubles, I’d say there are, probably, four outs that would have been home runs. Additionally, I think there are about six doubles that would have been home runs. That’s 10 extra home runs for Vinnie at Kauffman Stadium alone.

The other thing that Vinnie said that sticks with me is the last two words he typed: “neutral ballpark.” Kauffman Stadium was so big as to be an outlier in multiple ways. It was hard to hit home runs. And, importantly, it was hard to defend–with so much grass to patrol, there’s nowhere to hide a somewhat flat-footed slugger to eke out some more power. Additionally, playing half your games in an outlier ballpark brings its own challenges.

And in the press release announcing the change, general manager JJ Picollo mentioned just that:

We’ve discussed this possibility for years, and after much work by our Research & Development department, believe this will be a positive change for our baseball team. We wanted more consistency throughout the season, while making sure the specifics put us in the best position to succeed.

Of course, the Royals also have to pitch in this environment, too. But they have to pitch in other smaller parks half the time, and Kansas City’s trend towards valuing strikeouts more and more plays into this decision too. All told, it’s another reason to be excited for the new season.