World Series roofs: Fair or foul play?

This year's World Series could become the first played entirely indoors, with the retractable roofs at American Family Field and the domed Tropicana Field posing unique playing conditions. These structures are not merely passive coverings but can actively influence game outcomes, as demonstrated in a recent NLDS where a ball hitting a roof cable resulted in an out.

In Milwaukee, the American Family Field roof has specific rules: balls hitting it in fair territory are outs if caught, dead balls if over foul territory, and foul if hitting the roof over fair territory and landing foul. This came into play during the NLDS when a potential go-ahead home run hit a roof cable, leading to an out and a challenge that was ultimately upheld.

Tropicana Field presents its own set of challenges with a domed structure featuring four rings of catwalks above the playing surface. Specific ground rules dictate that fair balls hitting the lower catwalks (C and D rings) are home runs, while hitting the upper catwalks (A and B rings) results in a ground-rule double if they stay on the catwalk, or a ball in play otherwise. Foul balls hitting any catwalk are dead. The Tampa Bay Rays' stadium has a history of such incidents, with numerous fair balls impacting the catwalks.