What Constitutes a Balk?

The balk: an illegal act by the pitcher with a runner or runners on base, entitling all runners to advance one base; is probably the least understood infraction in all of baseball.

The rule centers on the actions of the pitcher and it's important that developing pitchers learn about the do's and don'ts of pitching, to avoid getting called for the balk.

In short, the intent of the balk rule is to prevent the pitcher from deliberately deceiving a base runner, and thereby gaining an unfair advantage over the runner. Umpires are instructed to rule based on the "intent" of the pitcher, if there is any doubt.

It's important to note for developing pitchers that once they step on the rubber, they have changed their status from "infielder" to "pitcher" and the rules governing pitchers are in effect. To change their status back to "infielder" all they have to do is step off the rubber with their pivot foot. Note that it's illegal to act like a pitcher when you're not on the rubber (i.e. go through pitching motions).

In the official MLB rule book, there are 13 different ways to balk.  Below you will find the shortened version of the MLB rules...

1. The pitcher makes their natural pitching motion but fails to throw the ball to home plate.
2. The pitcher feints a throw to first base, while touching the rubber, but fails to make the throw. Note that this rule applies to throws to first base only. The pitcher can fake a throw to second or third base, provided there are runners on those bases. Also note that if the pitcher steps off the rubber they don't have to throw.
3. The pitcher fails to step directly toward a base before throwing to that base. Note that you can't throw and then step. Also note that you have to step directly towards the base. There is no 45-degree rule, or mostly toward the base. Obviously it's the umpires judgement that governs.
4. The pitcher throws or feints a throw to an unoccupied base, except for the purpose of making a play. Note that it's okay to throw to second base if the runner on first base has already taken off, attempting a steal.
5. The pitcher makes an illegal pitch. Note that a "quick pitch" or pitching before the batter is reasonably set in the batter's box is an illegal pitch (it's alsodangerous). Make sure you wait for the batter to get ready, and remember that just being in the batter's box doesn't mean the batter is reasonably set.
6. The pitcher delivers the ball to the batter while they are not facing the batter. I've never personally seen thishappen, but I bet somebody actually tried this sometime.
7. The pitcher makes any motion naturally associated with their pitch when they are not touching the rubber.
8. The pitcher unnecessarily delays the game.
9. The pitcher fakes a pitch without the ball. Note that it doesn't matter whether you're on the rubber or not.
10. The pitcher, after coming to a legal pitching position, removes one hand from the ball (other than releasing the ball on the throw).
11. The pitcher accidentally or intentionally drops the ball. Note that you have to be touching the rubber before this is a balk.
12. The pitcher, while giving an intentional base on balls, pitches when the catcher isn't in the catcher's box. Note that the catcher has to start in the catcher's box and then quickly move outside to catch the ball.
13. The pitcher delivers from the set position without coming to a stop.

Those are the official rules governing the balk. Here are a few of the common mistakes you may see when developing a pitcher.

• Turning your shoulders towards first base to look at the runner after coming to the set position. Keep your shoulders still and turn your head. When you turn your body towards first base, you're making a move to the base and you have to step and throw.
  
• Not stopping after coming to the set position (see 13 above). I tell my pitchers to stop, take a breath, and then throw.
  
• Moving the ball to your mitt or from your mitt while standing on the rubber waiting to pitch (see 10 above). Remember that once you're standing on the rubber, you changed your status to "pitcher" and you need to be more careful.
  
• Getting confused when the runner takes off and stopping your motion to the plate to try and make a play on the runner. Once you commit to throw to the plate, you have to finish your throw.