Growing concern for fans' safety at baseball games could change MLB's 100-year-old "limited duty rule," known as the Baseball Rule, which means teams have the duty to warn but not protect fans from flying objects.

Under the Baseball Rule, courts have ruled that spectators attend ballgames at their own risk, while teams are protected from lawsuits of those struck by objects such as foul balls, Al Jazeera America reported.

During the late 1800s, before netting was put up, the area behind home plate was referred to as the "slaughter pen" because people often got hit and hurt by foul balls and debris from broken bats.

Two cases in the past four years have made their way through the judicial system and could threaten the limited duty rule. On Aug. 30, 2010, a line drive foul ball hit a girl in the head while she was sitting with her father behind the Atlanta Braves dugout at Turner Field. According to court documents obtained by Al Jazeera, the girl suffered "severe traumatic brain injury."

The child's father sued the Braves, which cited the Baseball Rule in moving to dismiss the case, but it has been taken to the Court of Appeals in the state of Georgia. In January, MLB filed an amicus brief in support of the Braves.

Another man sued the Kansas City Royals for a serious eye injury after he was struck in the eye by a hot dog wrapped in foil thrown by the team's mascot. The case was heard in the Missouri State Supreme Court on Sept. 11, 2013, after the Royals failed to get the case dismissed.

The plaintiff's attorney said a ruling could come any day now, Al Jazeera said.

Experts such as Gil Fried, a University of New Haven School of Business professor of the management of sports industries, argue that in the past 100 years, baseball has changed substantially, with players able to hit the ball harder, fan seating moving in closer and in-game entertainment distracting fans from the action.

"When this limited duty rule was first used, you had big fields, and sometimes fans were very far from the action," said Fried, also a frequent expert witness in ballpark injury cases. "A lot of times you had people who parked their cars, or buggies, in the outfield to watch because they were so far away. People sat in suits and ties and hats. But things have changed quite a bit."

Fried also said MLB should research the safety of "other areas of the ballpark -- above the dugouts, for example," Al Jazeera reported.

MLB spokesman Patrick Courtney told Al Jazeera he is unsure if anyone has done a study of the speed of baseballs flying into the stands.

"Due to a number of factors, including the different configurations and dimensions of our ballparks, as well as local codes and laws, each club individually determines what is appropriate within its park," Courtney said.