This year's World Series will be contested by a pair of franchises that share a key similarity.
Toss aside the narratives about market size, playing styles and league-best records. We're talking about the fact that both the Tampa Bay Rays and Milwaukee Brewers play inside stadiums that have roofs.
Now, not all domed stadiums are created equal -- the roof of Milwaukee's American Family Field is retractable, while that of Tampa Bay's Tropicana Field is permanent -- but both venues for this year's Fall Classic add a potential quirk to gameplay that emerged once in each team's respective playoff run: a "roofball." The concept is simple: sometimes, a ball is hit so high, at such an acute angle, that it strikes the stadium roof (well, not usually the roof specifically. But we're working in broad strokes here).
In the ninth inning of Game 1 of the Brewers' divisional round series against the San Diego Padres for instance, a potentially game-changing fly ball by Padres infielder Ty France struck a roof cable at American Family Field, falling back into play for a flyout. And a few days later, in Game 2 of the Rays' divisional round matchup with the New York Yankees, a pop fly by the Yankees' Spencer Jones ricocheted off of one of Tropicana Field's catwalks before falling back into the field of play for another out.
And so the World Series of roofball is here. Is the term perhaps overblown, since the two playoff roof hits in quick succession were more coincidental than predictive? Almost certainly. But does this make for a fun excuse to dig deep into a silly secondary angle of an already fun on-field matchup? Absolutely.
Here's everything you need to know about the World Series, from the lens of stadium architecture.
So what's the tale of the tape for each roof? Dimensions? Features?
The Brewers' website offers a simple facts and figures sheet that provides us with some easy answers: American Family Field's roof spans 600 feet, covering 10.5 acres, is 330 feet above the playing field at its apex and weighs 12,000 tons. The Rays don't offer as direct of a statistical breakdown, but fear not, Tropicana Field has its own brief fact file as well. Repaired ahead of the 2026 season after damage sustained in Hurricanes Helene and Milton, the roof, in addition to standing 225 feet above the infield at its peak, is notably made up of 24 individual panels weighing 5,000 pounds each.
Do ball-on-roof collisions happen often?
Unfortunately for fans who want chaos and oddities, the answer is no.
Despite two notable "roofball" moments occurring within a span of a few days during the divisional round of this year's playoffs, such instances aren't exactly commonplace. That doesn't mean there haven't been some famous examples, though.
American Family Field is the far less likely place for something to happen. In fact, France's brush with the American Family Field's roof was just the third time in the ballpark's history a collision occurred. The most notable of the other two also came in the postseason. In 2008, Phillies outfielder Jayson Werth's fly ball to left field struck the park's roof truss and redirected down toward the infield. Brewers third baseman (and future manager) Craig Counsell made a diving catch for an out. The unlikely sequence had no bearing on results -- Philadelphia would go on to win the game, series and later World Series.
At Tropicana Field, however, collisions are a little more common, and as such the lore for a notable roof strike goes a little deeper. In 2016, for instance, Miguel Sanó became the first person to actually hit a ball to the Trop's roof, as opposed to the more frequent catwalk strike (more on that in a bit).
OK, so how do the rules here actually work?
An interesting quirk stemming from the reality that ballpark roofs are not monolithic is the fact that there are different rule specifics for different stadiums with regard to balls making contact with park infrastructure.
At Tropicana Field, the rules center on the traditional culprit in a roof hit -- which isn't actually the roof itself, but a series of catwalks underneath the roof -- rings A, B, C and D, with the alphabetical names correlating to the respective catwalk's height and circumference. The rules vary slightly based on which catwalk (and as such where above the field) the ball strikes, but the general themes are similar. The Rays provided the following explanation of their stadium's specific protocol to MLB.com:
"The four catwalks located above the playing surface at Tropicana Field are labeled the A-, B-, C- and D-rings, with the lowest being the D-ring. Any fair ball that hits the lower two catwalks (C, D) is a home run. A fair ball that hits one of the top two catwalks (A, B) is in play. Any fair ball that stays on one of the top two catwalks is a ground-rule double. A foul ball that hits one of the catwalks is a dead ball."
Without the issue of catwalks to negotiate, the rules for American Family Field are a little more straightforward. The Brewers' webpage on MLB.com offers the following guidelines:
"Batted ball striking roof, roof truss or roof cable over fair territory: In Play. If caught by fielder, batter is out and runners advance at own risk. Batted ball striking roof, roof truss or roof cable over foul territory: Dead Ball"
Can we get an expert's take on all this?
I'm glad you asked. We've tapped Dr. Benjamin Flowers, a professor of architecture at Ohio State who has a specific expertise in stadiums, to give his thoughts. On baseball? Don't be silly. We had him compare, contrast and grade the two venues and their respective roofs.
Flowers described Tropicana Field as "a rather generic stadium: round, domed and wrapped in a relatively blank façade," noting that this design can likely be attributed to Tropicana being built to attract a nonexistent baseball team, not enhance the experience of an existing one. In contrast, he highlighted American Family Field's greater distinctiveness -- and the presence of a retractable roof instead of a fixed one.
"Where Tropicana Field is generic -- built to host both arena football and baseball and sporting a fixed roof -- American Family Field is a bespoke baseball stadium with an equally distinctive retractable roof," Flowers wrote in an email to ESPN. "The roof design is also bespoke -- a fan of roof sections rotating off a fixed point behind home plate can go from open to closed in about ten minutes."
Flowers said, perhaps unsurprisingly given his above comments, that his preference would be toward American Family Field's construction, highlighting the catwalk concern at Tropicana.
"Catwalks hanging from the sloped roof structure at Tropicana Field range from as little as 59 feet to a max of 194 feet above the field. Given that batted balls in baseball can routinely be hit 120-150 feet into the air, this means batted balls can (and regularly if not often do) hit these catwalks" Flowers wrote. "American Family/Miller [Park] does a much better job of enclosing the game of baseball without interfering with batted balls."
The professor's final grades? A C+ for Tropicana Field (citing "roof issues, generic façade, located at a freeway intersection far from fan base"), and a B+ for American Family Field (adding the caveat that A-grade stadiums are rare).
What has to happen for the ball to actually hit the roof in the first place?
Unfortunately, we don't quite have the time to perform an exhaustive research project on the exact angles and trajectories batted balls would need to take to collide with the roof -- or roof tresses, or catwalks -- in every possible instance (and yes, we asked).
We can, however, lean on StatCast to offer data on the two that have already occurred in this playoffs as immediate points of recent reference. France's flyout, for instance, had an exit velocity of 105.3 miles per hour, and a launch angle of 49 degrees. Jones', on the other hand, had an exit velocity of 106.4 miles per hour, with a launch angle of 44 degrees.
Both 'roofball' moments from these playoffs resulted in outs. How do fielders handle such occurrences?
Professionals are professionals for a reason. Every player on the field at any given time is paid quite a bit of money to know how to handle a falling baseball, bizarre deflections or not. As seen in both France's and Jones' flyouts, fielders are plenty well-drilled at locating a ball and communicating among themselves to determine who has the best angle on it.
But that doesn't mean there aren't some factors that can cause chaos. Ian Happ has the equanimity on this matter that you'd expect of a man with four Gold Gloves to his name, but even he noted that external forces can make a difference -- ironically observing that actually he finds things easier when American Family Field's roof is fully closed, as complete cover blocks out any possibility of wind swirling around.
"The way they half close the roof now it's not bad," Happ told ESPN's Jesse Rogers. "Used to be really hard for day games in left but it's not bad anymore. Easy when it's closed. Can be a little weird when the panels are open and the wind swirls."
Tropicana Field isn't to be trifled with. Practice and preparation, however, can be key in mitigating any effects -- with one particular bit of sound advice being to position oneself further behind the ball.
"So The Trop, it's a difficult background for somebody that's never played there. Because I've went and caught flyballs my whole life, but I've never dealt with a two-tone background, if that makes sense. When you look up, you have not only the canvas, but you also have the shadows that the catwalks create and the only thing you can really do to prepare yourself is to get reps in batting practice or have the coach hit you fungoes," one AL East outfielder told ESPN's Jorge Castillo.
"A piece of advice that I got was just to play the ball back further than you think because your depth perception is messed up and it's safer to play behind the ball more so than in front of the ball. But, yeah, I think visually the contrast is difficult with the canvas and with the catwalks and the shadows that it creates."
Will any of this advice be relevant to Brewers and Rays fielders this Fall Classic? Perhaps not, since both teams will naturally be well-adjusted to the possibility of chaotic bounces due to their respective home stadiums. And, admittedly, it's unlikely we'll even see another roof bounce this World Series anyway.
But one maxim remains true for fans and players alike, in the interest of peak preparation: Beware not the roof, but the trusses and catwalks below.