In this tutorial, we will learn about two (2) types of sacrifice plays:
Sacrifice plays are any time a batter hits the ball and is subsequently thrown out, but runners already on base advance or score because of the fielders being occupied with throwing the batter-runner out.
Sacrifice plays are always used when there are less than two outs, and there is at least one runner in scoring position (on either second or third base). They are a good way to acquire runs without needing an exceptional hit.
A sacrifice fly (often called a sac fly) is slightly different from a sacrifice bunt, and is a more common occurrence. Unlike a sacrifice bunt, which is used to advance runners, the purpose of a sacrifice fly is to advance a runner to home plate to score (this is also called driving a runner home).
How A Sacrifice Fly Works
A sacrifice fly goes as follows: A batter hits the baseball into the outfield, or foul territory outside the outfield. A fielder catches the baseball, putting the batter out. Once the baseball has been caught, a runner (usually at second base or third base) runs to home plate while the fielder with the baseball throws the baseball to the catcher so he can put the runner out at home plate. If the runner safely reaches home plate before the catcher has the baseball/can put him out, he scores. Other runners on base can also advance, as long as they are not put out.
Batters most commonly use bunts for the purpose of advancing runners on base, at the expense at getting out themselves. This is called a sacrifice bunt: a batter will bunt the baseball, the fielders will field the bunt and throw it to first base to put the batter-runner out, thus giving time for the runners already on base to advance.