How is it possible ….
 

That there is no definition in the rules of baseball as to what constitutes a swing? It’s the most basic act in the game. And it’s totally undefined.

Bizarre.

When the replay system comes into effect, it will be defined as the top of the bat pivoting more than 45 degrees from the knob. I can see why it wasn't defined before the age of technology and instant replay. In real time, it's impossible for the ump to do anything other than use discretion about whether a batter has "offered" at a pitch.

Assumption
 

I always figured it was if the bat got to straight out across the plate or further….

I have always known it to be a bat that does not break the plane of the top of home plate.

There is no rule as to what physically is a swing vs a checked swing. Totally a subjective call. No formal criteria.

I always thought that was the rule because Of announcers mentioning it millions of times - also If the batter’s wrist “break” - “ how is it possible this is not in the rulebook ?” Is a good point, wouldn’t take much effort to make it a rule .. With today’s technology it could even be reviewable if need be

I agree. It is indeed bizarre for a thread dealing with what constitutes a swing in baseball not to mention this in the title. "Teaser" titles are a form of phishing for readers and as such are discouraged on many forums.

My original post was slightly off. . . .just slightly.

The baseball rule apparently defines a swing as an attempt to strike at the ball.

But beyond that no specifics. And no definition of what a checked swing is.

When we were kids playing tennis ball baseball, some kids, when they had 2 strikes, would take a hard half-swing. If they hit the ball, it would go far enough to be a hit. If they missed, it would be a "check swing" because they didn't break their wrists, the bat didn't go beyond the plate, and it didn't go past perpendicular.

So, we figured out how to "game" that non-rule a half century ago.