Foul pole or attached screen
Glove, hat, or any equipment or apparel deliberately thrown by a fielder in an attempt to stop or deflect a fair ball that, in the umpires' judgment, would have otherwise been a home run.[3]
Any fixed object where a particular ballpark's ground rules specifically state that a batted ball striking that object is a home run. This usually applies to objects such as scoreboards or architectural features which are beyond the outfield fence in fair territory, but are located such that it is difficult for an umpire to quickly judge their position in relation to the field from several hundred feet away.
If a fly ball hits the foul pole (orange pole on the right), the ball is fair and a home run is awarded to the batter
A home run accomplished in any of the above manners is an automatic home run. The ball is considered dead, and the batter and any preceding runners cannot be put out at any time while running the bases. However, if one or more runners fail to touch a base or one runner passes another before reaching home plate, that runner or runners can be called out on appeal, though in the case of not touching a base a runner can go back and touch it if doing so won't cause them to be passed by another preceding runner and they have not yet touched the next base (or home plate in the case of missing third base). This stipulation is in Approved Ruling (2) of Rule 7.10(b).[3]
Inside-the-park home run
Main article: Inside-the-park home run
An inside-the-park home run occurs when a batter hits the ball into play and is able to circle the bases before the fielders can put him out. Unlike with an outside-the-park home run, the batter-runner and all preceding runners are liable to be put out by the defensive team at any time while running the bases. This can only happen if the ball does not leave the ballfield.
In the early days of baseball, outfields were relatively much more spacious, reducing the likelihood of an over-the-fence home run, while increasing the likelihood of an inside-the-park home run, as a ball getting past an outfielder had more distance that it could roll before a fielder could track it down.
With outfields much less spacious and more uniformly designed than in the game's early days, inside-the-park home runs are now a rarity. They are usually the result of a ball being hit by a very fast runner, coupled with an outfielder either misjudging the flight of the ball (e.g., diving and missing) or the ball taking an unexpected bounce. Either way, this sends the ball into open space in the outfield and thereby allows the batter-runner to circle the bases before the defensive team can put him out. The speed of the runner is crucial as even triples are relatively rare in most modern ballparks.