Defensive Interference

We've learned that interference is an infraction that is committed by the offense (base runners and batters, primarily). However, there is one special case where it's the defense that commits the interference – defensive interference, commonly known as "catcher's interference." All other infractions by the defense that impede offensive players fall under the rules for obstruction.

We're going to look closely at two related forms of defensive interference and call them by their familiar names:

Catcher's interference

The definition of defensive interference is very simple – just 18 words: "Defensive interference is an act by a fielder which hinders or prevents a batter from hitting a pitch."

The rule specifies "fielder" but in reality the catcher is the culprit in 99.9% of cases, which is why it's known as catcher's interference. That said, there is one edge case in which another fielder could possibly "hinder or prevent" a batter from hitting a pitch – that's when an infielder charges on a bunt attempt, but charges so aggressively that he somehow contacts the bat during the attempt, or conceivably the pitched ball before it arrives at the bat. But it's hard to picture this.

By far the most common scenario in which you have catcher's interference is the catcher placing his mitt such that it touches the bat during a batter's offer at a pitch. Sometimes the bat only glances the mitt and the batter puts the ball in play. Sometimes the bat hits the mitt solidly (sometimes injuring the catcher).

If the ball is put in play, you have a delayed dead ball. Let the play continue, then call time when the play is complete. We explain in the next section how to handle this. If, on the other hand, the ball is not put in play (either swing and miss, or foul ball), just call time and enforce the penalty. We'll look at both of these scenarios, plus a wrinkle in the rule that comes into play if there's a base runner stealing when the interference occurs.
 

Ball put in play: delayed dead ball

If you see catcher's interference and yet the ball is put in play, don't kill the ball. Allow action to continue. Once all action on the play has concluded, call time. At this point the team manager has the option of accepting the result of the play, OR, accepting the penalty. If the batter was put out on the play, he's probably going to accept the penalty. But not necessarily.

Take this scenario, for example. Say there are no outs and a non-forced runner on third (R3) scores on the play. The manager might want to overlook the interference and accept the out at first in order to get the run. Otherwise, if the manager decides to accept the penalty instead of the play, then R3 would have to return to third base and the run would come off the board. Again, this is manager's option.
 

Ball not in play: dead ball (slightly delayed)

If the ball was not put in play, there are no options. Just kill the ball, vocalize the infraction, and send the batter to first base. Other runners advance if forced. However, there's one big exception, so pause for a moment before you kill the ball to ensure you're not stepping on the exception.
 

A wrinkle: Base runner stealing when the interference occurs

Rule 5.06(b)(3)(D) adds a wrinkle to catcher's interference. If a runner is attempting to steal on a play in which catcher's interference occurs, the runner gets the base to which they stealing and the batter is awarded first base on the interference. Note that if the batter has put the ball in play and reaches first base safely, and all base runner advance at least one base safely, the interference is waved off.
 

The catcher's balk

I'm adding this information about the catcher's balk because it seems logical to group all of these infractions by a catcher together. There are two ways that a catcher's actions can cause you to call a balk (or illegal pitch with no runners on base).

Rule 6.01(g). If a runner on third base (R3) is trying to score by means of a squeeze play or steal, and the catcher or any other fielder steps in front of home base without possession of the ball, or touches the batter or the bat, the catcher is cited for the defensive interference, and the pitcher is charged with a balk ("catcher's balk"). The batter is awarded first base on the interference ("catcher's interference") and the ball is dead.

Note that this ruling applies only in this special case of a runner attempting to steal home. You see this now and then. The pitcher starts his delivery, but the catcher becomes aware that R3 is attempting to steal home, so the catcher tries to rush and in doing so steps in front of the batter to more quickly get the ball. That's interference.

The upshot here is that if the catcher commits defensive interference when a runner from third is stealing home, you don't have any manager options. Instead, you have this:

When giving intentional base on balls

And finally, Rule 5.02(a). If a catcher leaves the catcher's box before the pitcher delivers the pitch (as when giving an intentional walk), the pitcher shall be charged with a balk (with runners on base), or with no runners on, an illegal pitch (ball to the batter). (As leagues, including MLB, increasingly move to not requiring the throwing of four pitches to intentionally walk a batter, this rule is slowly becoming archaic.)

The truth is, I've never seen this enforced. Umpires (even in pro ball) appear to give a lot of leeway. In youth ball you sometimes see a catcher set up way outside the catcher's box for an intentional walk; in that case, just instruct the catcher to get back where he belongs.