What Is a Double Play in Baseball? Rules, Types & Scoring Explained

A double play in baseball is when the defense records two outs on the same continuous play. It requires at least one baserunner and fewer than two outs already made, and it’s one of the most valuable defensive plays in the sport because it can erase a rally in a single pitch. Understanding how double plays work — and why fans call turning one “the pitcher’s best friend” — is essential to reading any box score or baseball terminology glossary.

The Basic Rule

A double play can only occur when two conditions are met:

1. At least one runner is on base.
2. Fewer than two outs have been recorded in the inning (0 or 1 out).

If there are already two outs, the inning ends the instant the first out of the sequence is made, so a second out on the same play is impossible. This is why announcers say a double play “kills the inning” — it typically wipes out a runner and the batter in one shot, ending the threat two outs faster than usual.

The Classic Force Double Play

The most common version happens with a runner on first base and fewer than two outs:

1. The batter hits a ground ball to an infielder.
2. That fielder throws to second base, where a teammate steps on the bag to force out the runner coming from first (out number one).
3. The fielder at second immediately relays the ball to first base, beating the batter-runner for the second out.

Because neither runner needs to be tagged — both are forced to advance — this is called a force double play, and it’s by far the most frequent type turned in a real game.

How Double Plays Are Scored (6-4-3, 4-6-3, and More)

Official scorers record a double play by listing the defensive positions, in numerical order, that touched the ball. Standard position numbers are: 1 = pitcher, 2 = catcher, 3 = first base, 4 = second base, 5 = third base, 6 = shortstop.

Scoring	Sequence	Description
6-4-3	Shortstop → 2B → 1B	Most common double play; ball hit to short
4-6-3	2B → SS → 1B	Ball hit to the second baseman’s side
5-4-3	3B → 2B → 1B	Ball hit down the third-base line
1-6-3	Pitcher → SS → 1B	Comebacker to the mound
3-6-3	1B → SS → 1B	First baseman starts it, covers his own base at the end

A ground ball worked by the third baseman, shortstop, and first baseman in order (5-4-3) is also nicknamed an “around the horn” double play. See how each of these fielders lines up on baseball positions by number for a full breakdown of the numbering system.

Other Ways to Turn Two

Not every double play starts with a ground ball. Common variations include:

• Unassisted double play — a single fielder records both outs alone, such as a first baseman snagging a line drive and stepping on the bag before the runner can scramble back to first.
• Tag double play — the second out comes from tagging a runner rather than forcing him, often on a rundown or a runner caught off base after a fly-out.
• Strike-‘em-out, throw-‘em-out double play — a batter strikes out on a swinging or called third strike while a runner is thrown out attempting to steal, completing the double play at second or third.
• Line-drive double play — an infielder or outfielder snags a hard-hit liner for the first out, then throws behind a runner who had broken from the base, completing the “doubled off” second out.

The Slide Rule: Protecting the Pivot Man

Because the fielder turning the second half of a double play at second base is briefly vulnerable, MLB adopted Rule 6.01(j), the modern slide rule, in 2016. It requires a runner trying to break up a double play to make a “bona fide slide” — starting the slide before the bag, staying within reach of the base, and not changing paths just to hit the fielder. A runner who violates the rule can be called out for interference, and the umpires may also call the batter-runner out at first, completing the double play by rule even if the throw wasn’t in time. This rule followed several high-profile injuries to infielders on takeout slides and is now reviewable by instant replay.

This connects directly to how the defense records a force out in baseball — the runner at second in a double play is almost always out on a force, which is why the slide rule specifically targets force-play situations at the bag.

GIDP: The Hitter’s Side of the Stat

From the batter’s perspective, grounding into a double play is tracked as GIDP (Grounded Into Double Play), a counting statistic that has been kept since 1933 in the National League and 1939 in the American League. Hitters who put the ball on the ground often and run poorly tend to lead the league in GIDP, while burner-type hitters rarely appear near the top of the list because they can beat the relay throw to first.

Triple Plays: The Rare Extension

A double play’s even rarer cousin is the triple play — three outs on one continuous play — which requires the same basic setup (multiple runners on, fewer than two outs) but almost always needs an unusually lucky or well-executed sequence, such as a line drive with two runners going. Triple plays happen only a handful of times across an entire MLB season, which is part of why the routine double play is so prized: it’s the reliable, repeatable version of the same idea.

Why Double Plays Matter So Much

A double play doesn’t just record two outs — it removes a baserunner and denies the batter a chance to reach, all in a single pitch. That’s why pitchers who induce a lot of ground balls are valued highly by teams: with a runner on and less than two outs, a routine grounder can end an inning outright. It’s also why infield defense, particularly at shortstop and second base, is weighted so heavily in evaluating a team’s overall run prevention.

For more foundational rules like this one, start at the baseball terminology glossary or head back to the full baseball hub for MLB rules, records, and explainers.