Force play

Atlanta Braves first baseman Adam LaRoche (white jersey) puts out Cincinnati Reds pitcher Aaron Harang, the batter-runner, at first base. The effect is the same as a force out.

In baseball, a force is a situation when a baserunner is compelled (or forced) to vacate his time-of-pitch base—and thus try to advance to the next base—because the batter became a runner. A runner at first base is always forced to attempt to advance to second base when the batter becomes a runner. Runners at second or third base are forced only when all bases preceding their time-of-pitch base are occupied by other baserunners and the batter becomes a runner.

A forced runner's force base is the next base beyond his time-of-pitch base. Any attempt by fielders to put a forced runner out is called a force play. A forced runner is out (called a force out) when a fielder with the ball touches the runner's force base before the runner reaches that base. A forced runner also may be tagged out in the usual fashion as well; such a tag is still considered a force play if the tag is made before the runner reaches his force base. Any play on the batter-runner before he reaches first base is the same as a force play, though the rules technically do not include this in the definition of a force play.

A force on a runner is "removed" when the batter or a following runner is put out. This most often happens on fly outs—on such, the batter-runner is out, and the other runner(s) must return to their time-of-pitch base, known as tagging up.

Force outs may also be called on neighborhood plays, though this tradition goes against the rules.

Scoring

No run can be scored during the same continuous playing action as a force out for the third out, even if a runner reaches home plate before the third out is recorded. As a result, on a batted ball with two outs, fielders will nearly always ignore a runner trying to score, attempting instead to force out the batter or another runner.

An appeal play may also be a force play; for example, with runners on first and third bases and two out, the batter gets a hit but the runner from first misses second base on the way to third. After a proper appeal, this runner will be called out. This is a force out because the runner was out for failing to touch a base to which he was forced; this force out is the third out and thus the run does not score. However, most appeals are not force plays, because appeals usually do not involve a forced runner.