Baseball looks simple at first: pitch, hit, run. Then the umpire calls something that leaves half the crowd confused. A few rules come up again and again when people are new to the game, and once you understand them, the strange moments start to make sense. Here are the ones fans ask about most.
The Infield Fly Rule
This is probably the most famous puzzling rule. It applies when there are fewer than two outs and runners on first and second, or the bases are loaded. If the batter hits a fair pop-up that an infielder can catch with ordinary effort, the umpire can call “infield fly” and the batter is out straight away, whether the ball is caught or not.
The reason is fairness. Without the rule, an infielder could let the ball drop on purpose and then throw out two runners who had to stay near their bases. With the call, runners know the batter is already out, and they may still try to advance at their own risk, just as on any other fly ball.
The Balk
A balk is an illegal motion by the pitcher while there are runners on base. Pitchers are not allowed to fake a pitch to the batter, start their motion and stop, or throw to a base without stepping toward it in the proper way. The aim is to stop pitchers from tricking runners unfairly.
When a balk is called, each runner moves up one base. It can feel like a small technical call, but in a close game a balk can move a runner into scoring position or even bring home a run from third.
Tagging Up and the Dropped Third Strike
On a fly ball that is caught, runners must return to touch their original base before they can try to advance. This is called tagging up. You will often see a runner on third wait on the bag until the ball is caught, then sprint home. If they leave too early, the defense can appeal and get them out.
The dropped third strike surprises many people. If the catcher does not cleanly catch strike three, the batter may run to first as if they had hit the ball, as long as first base is empty or there are two outs. The defense then has to tag the batter or throw to first to complete the out.
Foul Balls, Bunts and Ground Rule Doubles
A foul ball counts as a strike, except when the batter already has two strikes. In that case the at-bat simply continues, which is why some batters foul off pitch after pitch. Bunts are the exception: a foul bunt with two strikes is strike three.
A ground rule double happens when a fair ball bounces and then leaves the field of play, for example by going over the outfield fence. The batter and any runners are awarded two bases from where they were when the pitch was thrown. Many fans still call it an automatic double.
Rules like these are part of what makes baseball such a thinking game. Next time you are at the ballpark, keep an eye out for them, and if you want to understand the numbers on the board as well, have a look at our page on baseball scores.