A rundown, often referred to as a pickle, is the situation in baseball where a runner gets caught between two bases. Typically, the runner realizes they will be tagged out if they try to make it to the next base, and they instead turn back towards the base they came from. In return, the defender with the ball will throw the ball past the runner to the other base. This will cause the runner to turn around, and run back towards the other base. This cycle will continue until either the runner is tagged out, he reaches one of the bases safely, or the ball is thrown away.
One of the most frequent ways a rundown can occur in a game is when a player gets picked off. A pickoff happens when the pitcher throws the ball to the base the runner is leading off from, and the ball beats the runner back to the bag. If the runner is not ready for this, and the ball beats them easily to the base, they may run away from the ball towards the other base, beginning a rundown.
Rundowns can also occur if the runner gets too aggressive, and tries to run one base too far. This often happens when a ball is hit into the outfield and relayed back to the infield quicker than expected.
Occasionally, runners will purposefully get into rundowns. This often happens when the batting team has a runner on first base and on third base. The runner on first base will get caught in a rundown to distract the defense while the runner on third base tries to reach home plate. The runner on first might get tagged out, but hopefully, the runner on third will score.
There are two ways fielders can get runners out in baseball: tagging the runner while holding the ball, or touching the base a runner is forced to advance to in force out situations. Rundowns occur in non-force out situations, so the fielders are required to tag the runner out with the ball. If the runner is touching a base, they can not be tagged out. If the runner is not touching a base when they are tagged, they are out. Runners who reach a base safely have to be careful to remain in contact with the base while the play is still going. Until there is a dead ball, runners can be tagged out anytime that they are not touching the base. If a runner slides too far and goes past the base, they can be tagged out.
Any base runner must stay in the basepath, an imaginary path six feet in width that stretches between consecutive bases. A runner may be tempted to leave the base path in a rundown to escape being tagged, but doing so will result in the runner being called out. Runners may move laterally to avoid being tagged, but only three feet to either side.
Fielders have to be careful not to obstruct the runner during a rundown. A fielder who does not have the ball is not allowed to obstruct, or make contact with, the runner in the basepath. If the fielder obstructs the runner, the play is over and the runner gets to advance to the next base. For example, if the obstruction takes place between first and second base, the runner is awarded second base. If the runner runs into the fielder outside of the basepath, the runner is out.
Only one runner is allowed on a base at any time. If two runners are touching the same base, the lead runner is safe while on base, and the following runner can be tagged out. This situation can potentially happen during or after a rundown.
If a run is scored on the same play that the third out of the inning is recorded, and it is not a force out, the run will count if it is scored before the third out is made. This can happen during a rundown if a player gets in a rundown in order to try to let a different runner score. To avoid a run being scored, the defense has to either tag the runner in the rundown before the other runner scores or get out the lead runner.