Ground rules

Universal

• Ball on the top step (lip) of the dugout is in play.
  • No equipment is permitted to be left on the top step (lip) of the dugout. If a ball hits equipment left on the top step it is dead.
• A player is not permitted to step or go into a dugout to make a catch.
• A player is permitted to reach into a dugout to make a catch. If a player makes a catch outside the dugout and the player's momentum carries him into the dugout, then the catch is allowed and the ball remains alive as long as the player does not fall while in the dugout.
• A batted ball in flight can be caught between or under railings and around screens.
  • A catch may be made on the field tarp.
• Batted or thrown ball lodging in the rotating signage behind home plate or along first base or third base stands is out of play.
  • Batted or thrown ball resting on the rotating signage behind home plate or along first base or third base stands is in play.
• The facings of railings surrounding the dugout and photographers areas are in play.
  • Any cameras or microphones permanently attached on railings are treated as part of the railings and are in play.
  • Any recessed railings or poles that are in the dugout and photographers areas are out of play and should be marked with red to mark them out of play.
• Robotic cameras attached to the facing of the backstop screen are considered part of the screen.
  • A batted ball striking the backstop camera is considered a dead ball.
  • A thrown ball striking the backstop camera is considered in play.
• A ball striking the guy wires that support the backstop is a dead ball.
• A ball lodging behind or under canvas on field tarp is out of play.
• A ball striking the field tarp and rebounding onto the playing field is in play.
• No chairs can be brought out of the dugout or bullpen and onto the playing field.
• All yellow lines are in play.
• A live ball striking the backstop screen or protective netting located on the field boundaries along the first and third base lines is in play.
  • A ball striking protective netting located behind out-of-play areas such as dugouts and photographer areas is dead even if it rebounds onto the field.
• Where a roof is present, a batted ball that becomes lodged in the roof above fair territory is dead and the runners including batter-runner are awarded two bases. Ballpark-specific ground rules may supersede this rule.
• On outfield walls composed of sections with different heights (e.g., Fenway Park, Oracle Park), a batted ball in flight that strikes a taller section of the wall in fair territory at a point higher than the top of the adjacent shorter wall, then bounds out of play over the shorter wall, is a home run.
  • Conversely, a batted ball in flight that strikes the shorter wall in fair territory then bounds out of play over the adjacent taller wall is a dead ball and the runners including batter-runner are awarded two bases.

Individual ballpark

Individual ballpark ground rules vary greatly from ballpark to ballpark. For the 2017 season, Citi Field, Kauffman Stadium, Target Field, Yankee Stadium, and Rate Field are the only MLB ballparks that do not have individual ground rules above the universal set.^[1]

Examples of ground rules that have been or are still in major league ballparks include:^{[citation needed]}

• Fenway Park (Boston Red Sox) – A fly ball that strikes the top of the ladder on the Green Monster and then bounces out of play is two (2) bases.
• Daikin Park (Houston Astros) – A batted ball striking the flagpole in center field and bouncing onto the field is in play; a ball striking the flagpole while in flight and leaving the playing field is a home run. The flagpole and the hill that it was on were removed following the 2016 season, and the rule has been removed from the specific ballpark rules list.
• Tropicana Field (Tampa Bay Rays) – A batted ball that hits either of the two lower catwalks (C Ring and D Ring) between the yellow foul poles is ruled a home run. The two upper catwalks (the A Ring and B Ring) are considered in play; a ball that touches either can drop for a hit or be caught for an out.
• Wrigley Field (Chicago Cubs) – A fair ball becoming lodged in the ivy on the outfield fence awards two bases to the batter and all runners; if the ball falls out of the ivy, it remains in-play.^[2]
• Citi Field (New York Mets) – Any fair ball in flight hitting the overhanging Pepsi-Cola sign is ruled an automatic home run. The sign has since been changed to "Coca-Cola" following new sponsorship in 2016, and no longer overhangs. The rule has since been removed from the specific ballpark rules.
• London Stadium (MLB London Series) – Any ball that hits the roof that overhangs home plate is ruled a dead ball.^[3]

Movement of retractable roofs

These ground rules only apply at ballparks featuring retractable roofs. As of the 2021 season, these are: Rogers Centre, Chase Field, T-Mobile Park, American Family Field, Daikin Park, and LoanDepot Park. Rules governing batted balls striking the roof are defined in each individual ballpark's ground rules.