The Offseason Monitor: Kauffman Stadium's New Dimensions
The Royals bring in the fences!
The Royals today announced big changes to Kauffman Stadium. They’ll be moving the fences in ten feet (in place) and lower them 1.5 feet. Read the full details here from MLB.com. Here’s the visual from that piece:
No change to straightaway center field, but a significant difference in the alleys. This Vinnie P bases loaded fly out is very possibly a grand slam with these changes:
Kauffman Stadium has long been tough for home runs. The overall run-scoring based park factor has been pretty neutral, because you get more doubles and triples with the big outfield (it’s the second biggest field by area) in exchange for the home runs it takes away. So maybe it won’t make a huge difference on raw scoring output from the Royals, but it’s sure to add more home runs to those games in KC this year, and that makes a big impact on the fantasy game.
My park factors:
→ Runs (All): 105
→ Runs (RHB): 109
→ Runs (LHB): 100
→ Home Runs (All): 86
→ Home Runs (RHB): 109
→ Home Runs (LHB): 89
I’m not the best park factor bro in the world, but the direction is probably accurate. In the last ten years, only Mike Moustakas (48 in 2017) and Vinnie Pasquantino (32 in 2025) have gone over 30 homers as a left-handed hitter. And it takes some bombs away from the elite all-fields power guys like Bobby Witt Jr. Here’s his spray chart from 2023-2025 on balls hit above 100mph and 20 degrees in angle:
They’re moving the left field fence in as well, so this is probably an even boost to both sides of the plate. But the park, in the past, has punished left-handed potential home runs more than right-handed ones.
We have a nice Barrel Details dashboard on the Main MLB Tableau. That will show you how rough some of these Royals had it last year. League-wide, 46% of barrels go for homers. In Kauffman, that number was 39% last year. Here are the numbers on everybody with at least five barrels in KC last year:
Only Yastrzemski (with six barrels) beat the league average. Witt had just ten homers in 34 barrels. A high percentage (41%) of his barrels were to center field, so those won’t be affected by this change, but a certain percentage of the 38% pulled and a bit of the 21% oppo he had last year would be homers with this new setup.
They’ll lose some doubles in exchange for these homers, which they’ll take, but it’s not guaranteed to shoot everybody’s slugging percentages through the roof. But a lot of flyouts will turn into doubles or home runs as well as these outfielders just run out of room. So it’s a boost to KC hitters, for sure. I took my best guess at the new park factors and re-ran the projections, and basically saw +2 homers for every Royals regular.
I’ve been quick to say, and last week I even proved, that my season-long hitter projections aren’t any better than the systems that are out there for free, but you get these updates a lot quicker, so that’s something!
My pitching projections last year turned out to be the best of the models I studied. I’m not banking a repeat of that, but in that spirit, we do have to remember that any good news to a team’s offense is bad news for the team’s pitchers.
Royals HR/FB Allowed in Kauffman Stadium, 2025
league average = 16%
Seth Lugo 19.7%
Noah Cameron 18.5%
Cole Ragans 13.6%
Kris Bubic 10.0%
Michael Wacha 8.6%
Lucas Erceg 5.9%
Carlos Estevez 3.0%
Lugo and Cameron were the only ones really getting hurt on their fly balls, and they had some very, very low numbers from Bubic/Wacha/Erceg/Estevez. It’s bad news in that regard. It’s particularly interesting to see Erceg and Estevez there. A double turning into a home run for a starting pitcher isn’t always a huge deal, but when it’s your high-leverage reliever, they’re often in there in a one-run game, and that would make all the difference.
Everything is balanced in life; there’s a negative to every positive. The Royals must be thinking this is more positive than negative for their overall team, though. Their offense hit fewer ground balls (40.4%) than their pitching staff gave up (42.3%) last year, so there’s a slight advantage in their favor on that front.
Cameron and Bubic are decent ground-ball pitchers, and Michael Wacha has a history of producing low HR/FB (under 10% in each of the last three seasons). Ragans doesn’t allow many balls to be put in play in the first place. So the only guy they’re really exposing here is Seth Lugo. And he can just go add another three pitch types to his repertoire, and that will give him something to live for.
It’s a move that makes sense, and it will be fun to see how it plays out. Chicks dig the long ball, and so do we!
The projections and (unfinished, but I’m getting close) player ranks are updated for all of this.