[DJWickham]

Jim, an excellent analysis of one of the most complex areas.

2 additional comments:

1. We haven't explored the difference between "A" and "B" obstruction.

An "A" obstruction occurs when there is a play being made on the runner who has been obstructed, and it immediately kills play. On the type A obstruction call, the ball is dead, time is called, and runners advance to the base the umpire judges they would have reached in the absence of the obstruction (which may simply be protection back to the last base, but often is an award of the next base). This sometimes punishes the offense. If immediately after the called obstruction, a fielder throws the ball out of play, all runner's won't necessarily get the extra base award from the overthrow. The ball was dead when the overthrow occurred.

A "B" obstruction occurs when there is no play being made on the obstruction runner. The umpire announces "that's obstruction" but does not call time until play ends. Only then, does the umpire call time. If a type B obstruction occurs and then the ball is thrown out of play, the offense will receive the additional advances (if any) awarded on the overthrow. The delay gives the umpire time to see what actually happened as a result of the obstruction, rather than make a judgment about what probably would have happened.

There appears to be no such delayed call treatment for interference (except a batter's interference with a catcher's throw or play). If a runner interferes, the ball is immediately dead on the "that's interference" call and the appropriate penalty assessed.

I think one of the problems with type A obstruction and almost all forms of interference is that the umpire is forced to stop play and make a judgment about what would have happened. The rules rarely permit the affected side to "waive the penalty and take the play" when something unusual happens immediately after the call.


2. It is obstruction if a fielder feigns a tag on a runner, but good baseball if the fielder (while out of the baseline) feigns that the ball is about to be caught on a play and forces the runner to slide or otherwise dupes the runner into thinking a fly ball was caught. Why is faking a tag always obstruction?