Obstruction - Rule 7.06
Obstruction is called when the defense hinders the runners ability to run the bases. There are two different applications of the rule. One causes an immediate dead ball and the other is delayed dead. If a play is being made on a runner who is obstructed, the ball is immediately dead. If no play is being made the ball is delayed dead.
Rule 7.06 states: "Obstruction is the act of a fielder who, while not in possession of the ball and not in the act of fielding the ball, impedes the progress of any runner."
If a fielder is about to receive a thrown ball and if the ball is in flight directly toward and near enough to the fielder so he must occupy his position to receive the ball he may be considered "in the act of fielding a ball." It is entirely up to the judgement of the umpire as to whether a fielder is in the act of fielding a ball. After a fielder has made an attempt to field a ball and missed, he can no longer be in the "act of fielding" the ball.
For example: an infielder dives at a ground ball and the ball passes him and he continues to lie on the ground and delays the progress of the runner, he has obstructed the runner.
As with interference, obstruction is also a tough judgement call. Contact between the runner and fielder is not necessary to meet the definition. If a runner must slow down or alter his path to avoid a fielder who is not in possession of the ball or in the act of fielding, he has been obstructed.
If no play has been made on the runner at the time he is obstructed, the play continues. The tough part comes when the play stops. The umpire will award the runner the base to which the umpire believes he would have reached had he not been obstructed.
For example: the batter hits the ball in the gap for what looks like an easy double. As he rounds first, the fielder is in his path and they collide. The batter stops at first. The umpire will award the runner second base if he believes the runner would have made it there had he not been obstructed.
It does not matter where the obstruction occurs. If a runner is obstructed at first base and the umpire believes he could have made it to third base, he will be awarded third. The umpire must be the judge. If, in the umpire's judgement, a runner is slowed down by one step at first and then is thrown out by five steps at third, the out should stand.
An immediate dead ball obstruction is called when the obstruction occurs while a play is being made on the runner.
For example: a runner on first is attempting to reach third on a hit. He is obstructed by a fielder between second and third as the throw from the outfield is heading toward third. This is a play on the runner. The umpire should call "time" when the obstruction occurs and award the runner third base. Another example is a run down play. It does not matter which way the runner is heading. If he is obstructed while being played upon in a run down, he is awarded at least one base beyond the last one held.