Tag out

Runners attempting to advance are sometimes thrown out, which means that a fielder throws the ball to someone covering the base, who then tags the runner before he touches the base.

For example, when a sharply hit ball is caught on one hop by the first baseman, he might immediately tag out the runner at first who is forced to advance to second, but when this is done, a runner already at second is no longer forced to advance to third base.

When an attempt to tag a baserunner has been initiated by a fielder in possession of the ball, then an imaginary base path is formed which is 3 feet (0.91 m) wide, extending from the runner to the base that the runner is trying to reach safely.

[1] Also, if the fielder drops the ball after the tag, the runner is safe.

[2] In historical variations of baseball, runners could be retired if the ball was thrown directly at them while they were not on a base, a practice referred to as "soaking" or "plugging".