For most of baseball's history, protective netting at stadiums only covered field-level seats behind home plate, which are typically the most expensive seats in stadiums.
But a number of notable instances of people being struck by batted balls, some of whom were young children, has prompted baseball teams to expand netting.
During Wednesday's MLB Winter Meetings, Commissioner Rob Manfred said all 30 MLB teams will now expand netting to extend "substantially" past the dugouts. This announcement goes beyond a 2015 study which recommended netting extend from dugout to dugout.
Some teams were already planning on expanding netting in 2020 with several teams planning on expanding netting from foul pole to foul pole. The Washington Nationals announced in June plans to expand netting down the lines.
In the last two years, two notable incidents seemed to prompt action from baseball officials.
In 2017, Todd Frazier, then of the New York Yankees, drove a foul ball down the line, which struck a girl behind the third-base dugout. The incident drew an instant reaction from players.
"I don't care about the damn view of a fan or what,'' Twins second baseman Brian Dozier told reporters after the game. "It's all about safety. I still have a knot in my stomach."
Then in May, Chicago Cubs hitter Albert Almora struck a toddler sitting down the left-field line. The incident caused Almora to drop to his knees in grief as soon as the ball left his bat.
The child was carried away to receive medical attention. According to MLB.com reporter Brian McTaggart, Almora went to a security guard to find out the child's condition. He then shared a hug with the guard and multiple teammates.
The incident involving Almora was part of the reason why the Nationals decided to take action on expanded netting.
"Over the past few weeks, we have seen several fans injured by bats and balls leaving the field of play at other stadiums," Nationals owner Mark D. Lerner said back in June. "I could not help but become emotional last month watching the Astros-Cubs game when a 4-year-old little girl was hit by a line drive. I can’t imagine what her parents must have felt in that moment. And to see the raw emotion and concern from Albert Almora Jr. was heartbreaking. Further extending the netting at Nationals Park will provide additional protection for our fans."
Even with the risk to fans of serious injury at baseball games, the expansion of netting has been controversial. Some fans argue that expanding netting obstructs the view from the seats, and takes away opportunities to catch foul balls.