The teams are the latest to respond to an incident at Yankee Stadium last September, in which a girl was seriously injured when hit by a foul ball.
Within 24 hours of that incident, the Cincinnati Reds, Colorado Rockies, San Diego Padres and Seattle Mariners all announced plans to extend protective netting next season. Commissioner Rob Manfred declined to mandate the extension of netting beyond the seats behind home plate, preferring that teams make that decision on their own.
All but a handful of teams have announced plans to extend netting. Manfred could address the situation at the owners' meeting next week.