Tagging Up and the Sacrifice Fly: Rules, Timing and Scoring
A runner may advance on a caught fly ball only after retouching his base at the moment of the first touch. How tagging up works, how appeals punish early departures, and how the sacrifice fly is scored.
A fly ball that is caught is an out, but it is not necessarily the end of the play. Every runner on base has a decision to make in the second or two it takes the ball to come down: stay put, or touch the base and then run. That decision is called tagging up, and the rule behind it is simple to state and easy to get wrong. A runner may advance on a caught fly ball only after he has had a foot on his base at the moment the ball is first touched by a fielder. If he leaves too soon, he must come back and touch the base again, and the defense can get him out if he does not.
The sacrifice fly is the scoring side of the same play. When a batter hits a fly ball that is caught with fewer than two outs and a runner scores after the catch, the batter is not charged with a turn at bat and is credited with a run batted in. The batter made an out, but he did something useful with it, and the scoring rules recognize that by keeping the out off his batting average.
This article covers both halves. It explains exactly when a runner is allowed to leave, what happens when he leaves early, how the defense appeals, how the sacrifice fly is awarded and what it does to a hitter's statistics, and how the decision to tag up fits into strategy. Rule details are described in general terms, because the official rule book is the final word; check it for the exact wording.
The tag-up rule in plain terms
The rule rests on a single moment: the instant a fielder first touches the batted ball. If a runner is on his base at that moment, he may leave as soon as the ball is touched, whether or not the fielder holds on to it. If the runner has left the base before that moment, he is not permitted to advance. He must go back, touch his base again, and only then may he try for the next one.
Two words in that description matter. The first is touch. The runner does not have to wait for a clean catch, a firm grip or the umpire's signal. The moment the ball first brushes a fielder's glove, the runner may go. This is why you will sometimes see a runner start for the next base when an outfielder juggles the ball: he is allowed to, and the juggle makes the play easier, not harder.
The second word is first. The runner's release is tied to the first touch, not to the last one. If an outfielder deflects the ball and a teammate then catches it before it hits the ground, the play is a catch and the runner may advance after the first deflection. A runner who stood on his base through the deflection and left on the second touch was never in danger of breaking the rule; the one who left before the first touch was.
What counts as a catch
A tag-up only applies when the ball is caught. If a fly ball falls untouched to the ground, or is touched and then hits the ground before a fielder controls it, nobody has been put out, and the runners are free to advance as the ordinary rules of force plays and tag plays dictate. For an explanation of those, see Force Plays and Tag Plays: How Umpires Decide Which Applies.
For a fair or foul fly ball to be a catch, the fielder must hold the ball securely in his hand or glove and show control of it; a ball that pops out during a transfer is judged by the umpire on whether he had control and voluntarily released it. A fielder who catches a ball and then crashes into a wall and drops it has still made the catch, provided he held it long enough to show control, and the runners may tag up from the moment he first touched it. Umpires, not rule book language, make the judgment on the field.
The rule applies to foul balls as well. A fly ball caught in foul territory, for example near the third-base dugout, allows a runner on third to tag up and try to score. This is why you will occasionally see a deep foul fly turn into a run, particularly in the ballparks with large foul territory. The batter in that case is credited with a sacrifice fly if all the other conditions are met, even though the ball never landed in fair territory.
What happens to a runner who leaves early
A runner who leaves a base before the ball is first touched, and then sees it caught, is in trouble. He has two choices: return to his base and touch it, or keep running and hope the defense does not notice. There are two ways the defense can punish him.
The first is a live-ball play. Because the ball is still in play after the catch, the fielder may throw to the base the runner left. If the throw reaches the base, and a fielder with the ball touches it before the runner gets back, the runner is out. This is called being doubled off, and it turns a single out into a double play. The runner did not have to do anything wrong in the sense of breaking a rule; he simply was not where he needed to be when the catch was made.
The second is an appeal. If the runner left early, never came back and kept running, the defense may appeal. An appeal is a request that the umpire rule on a missed or left base. The defense makes it by putting the ball in play, throwing to the base the runner left and touching it, and then asking the umpire for the call. The umpire does not call the runner out for leaving early on his own initiative; somebody on the defense has to ask.
The appeal rules
Appeals are governed by timing. A defense that wants to appeal a runner for leaving early must do so before the next pitch or the next play. Once the pitcher begins his next delivery, or any other play is attempted, the right to appeal the earlier mistake is gone. If the infraction happened on the last play of an inning, the defense may appeal until the pitcher and all of the infielders have left fair territory on the way off the field.
This produces a standard sequence at all levels. A runner on third tags up on a fly ball to right field, leaves a fraction early and scores. The pitcher takes the throw back from the catcher. He steps off the rubber and throws to the third baseman, who touches the bag. The umpire at third, who watched the runner, rules whether he left before the catch. If he did, the runner is out, and the run does not count.
A runner who is called out on appeal has not scored, so his run is erased, and the batter is not credited with a sacrifice fly or a run batted in for it. The batter is charged with an ordinary fly out. The runner's mistake cost the team the run and cost the hitter a statistic he had earned.
A defense that appeals at the wrong base, or that fails to appeal at all, loses the chance. Umpires will not remind a team of its options, and many runners leave early every season without being caught because nobody on the defense asked. This is the reason coaches teach runners to leave on the first touch rather than the instant they think the ball is caught, and the reason third-base coaches say "back" and "go" so loudly.
The time play and the third out
There is one more timing wrinkle, and it affects whether a run counts. If a runner crosses the plate before the third out of the inning is made, the run usually counts. But there are exceptions: a run does not score if the third out is a force out, if the batter is put out before reaching first base, or if a preceding runner is declared out on appeal for failing to touch a base.
On a fly ball with two outs, the catch itself is the third out, so nothing that happens afterward can score. With fewer than two outs, the tag-up becomes a race. A runner on third who leaves on the catch is trying to score before a possible third out on another runner, and the defense is trying to retire a second runner before he does. That is a time play, and the umpire has to decide whether the run crossed the plate before the out was made.
An example: a runner is on third and another on first with one out, and the batter hits a fly ball to right field. The runner on third tags up and scores. The runner on first, who left early, is doubled off. If the throw to first gets there before the runner on third touches the plate, it is the third out and the run does not count. If the runner scored first, the run counts, and the batter gets a sacrifice fly. The sequence of a few tenths of a second decides it.
How the sacrifice fly is scored
The scoring rules (Rule 9.08 in the official book) say a batter is credited with a sacrifice fly when four things are true. There are fewer than two outs. The batter hits a fly ball or a line drive. It is handled by an outfielder, or an infielder who has run out into the outfield, in fair or foul territory. And a runner scores as a result: either he scores after the ball is caught, or the ball is dropped and, in the scorer's judgment, the runner would have scored after the catch had it been made.
The last condition is the one most often overlooked. If an outfielder drops a routine fly ball and the runner on third scores, the batter still gets a sacrifice fly if the scorer believes the runner would have scored anyway. The fielder is charged with an error, but the batter is credited with the run batted in and the sacrifice. If the scorer decides the runner would have stayed at third had the ball been caught, no sacrifice is awarded and the play is scored like any other ball put into play.
A sacrifice fly may be awarded even if the runner scoring is not the one on third. A runner on second can score after a catch on a long fly to the wall; in that case the batter is credited with a sacrifice fly just the same. A sacrifice fly always carries a run batted in, because the run that scored after the catch is the reason for the credit.
Three things do not produce a sacrifice fly. A ground ball that scores a run is not one, even if the batter intended to move the runner. A fly ball with two outs is not one, because the catch ends the inning. And a pop-up caught by an infielder in the infield is not one, even with a runner scoring, since the rule limits the credit to balls handled by outfielders or by infielders in the outfield.
What the sacrifice fly does to the numbers
The sacrifice fly is an unusual statistic because it is treated differently by different formulas. It does not count as an at-bat, so it does not lower the batting average or the slugging percentage. It does count as a plate appearance, and on-base percentage, which is hits plus walks plus hit-by-pitches divided by at-bats plus walks plus hit-by-pitches plus sacrifice flies, treats it as an out. And it gives the batter a run batted in.
A worked example shows the effect. Suppose a hitter has 100 hits in 400 at-bats, and another 10 plate appearances ended in sacrifice flies. His batting average is .250 (100 divided by 400), because the sacrifice flies are not at-bats. If the sacrifice flies had been counted as at-bats, the average would have been 100 divided by 410, which is .244. The difference of six points is the reason hitters are not penalized in batting average for productive outs. On-base percentage is less forgiving: with 40 walks and no hit-by-pitches, that same hitter has an on-base percentage of .311 (140 divided by 450), where leaving the sacrifice flies out of the formula would give .318 (140 divided by 440).
The sacrifice bunt is handled differently. A sacrifice bunt is not an at-bat either, but the official on-base formula leaves it out of the denominator, while the sacrifice fly is included. The two plays are cousins that the record book treats as only partly related.
The sacrifice fly has not always been scored this way. It first appeared in the scoring rules in the early 1900s, was dropped and restored several times over the following decades, and has been a permanent part of the rules since 1954. In the historical record, which carries sacrifice flies as a column, the career leaders are Eddie Murray with 128, Cal Ripken with 127, and Albert Pujols and Robin Yount with 123 each, through the 2025 season. The statistic is a quiet marker of longevity and of hitters who drove in runs in lineups that put men on third.
When tagging up is a good idea
Whether a runner should tag up depends on three things: the depth of the ball, the arm of the fielder and the number of outs. A deep fly ball to center field is almost always worth a try for a runner on third, because the throw has to travel a long way and the runner has a short run. A shallow fly ball to a strong-armed right fielder is a gamble the runner will often decline.
The count of outs sets the stakes. With no outs, a runner on third will usually score on a fly ball of any real depth, and the offense gives up an out for a run. With one out, the same play is still worthwhile. With two outs, the catch ends the inning, so the question never arises. A runner on second faces a different problem: he can tag up and move to third on a medium fly, putting himself in position to score on another fly or a ground ball, but he also takes a risk of being doubled off if he misjudges the fielder's depth.
Hitters approach the situation accordingly. With a runner on third and fewer than two outs, a batter will look for a pitch he can lift deep enough to score the runner, and he will often take a pitch that is hard to elevate. For more on how the strike zone itself is defined and called, see The Strike Zone: Its Official Definition, Its History and Why It Is Hard to Call.
Defenses respond with the infield in, which cuts off a run on a ground ball but lets more ground balls through, and with outfielders who play shallow enough to threaten the runner, which raises the chance of a ball over their heads. Positioning choices like these are the same kind of trade-off discussed in The Shift Restrictions Explained: Where Infielders Must Stand.
Common mistakes and common questions
Runners get tag-ups wrong in three ways. They leave before the ball is touched, which is the cheapest mistake to avoid and the most expensive to make. They watch the ball instead of the fielder, so they miss the first touch. And they leave early on a fly ball that looks uncatchable, then see it caught, and find themselves too far from the base to get back.
Can a runner tag up on a foul fly? Yes, the same rule applies, and a runner on third can score on a caught foul fly.
Does a sacrifice fly count as an at-bat? No. It is a plate appearance but not an at-bat.
Is every fly out that scores a run a sacrifice fly? If there were fewer than two outs and the run scored after the catch, yes.
What if the outfielder drops the ball? The runner is not required to tag up on a ball that is not caught. If the run would have scored anyway, the batter is still credited with a sacrifice fly.
Can the umpire call a runner out for leaving early without an appeal? No. The defense must appeal.
What if a runner leaves early but the defense does not notice? The run counts, and the batter gets the sacrifice fly. The right to appeal expires with the next pitch or play.
Where to go next
To see how the rule applies when contact with a runner is involved, read Obstruction Versus Interference: A Guide to Two Rules Fans Mix Up. If you keep score, the scoresheet tool shows how a sacrifice fly is recorded, and the stat calculator lets you test the formulas yourself. The rules and umpiring topic page collects more explainers, and the official rules are published at MLB.com.