Baseball Rules: Tagging Up For Beginners

The game of baseball contains some rules that are difficult to understand and the one rule I’ve noticed a lot of new players struggle with understanding is the tag up rule. When you’re a baserunner, the goal is to advance to the next base, but the tag up rule actually prevents you from advancing. What is the tag up rule in baseball?

Baserunner on first base is watching a ball hit into the outfield with overlaying text that reads "Baseball Rules: Tagging Up For Beginners"

The tag up rule is when baserunners are required to touch the base they were occupying when the play began. The tag up rule is enforced when there are less than two outs and a fielder catches a batted ball before it touches the ground. Failure to tag up can result in an out.

In this article, we’ll cover everything you ever wanted to know about the tag up rule. This includes things like when to tag up, when not to tag up, and why runners can advance while a fielder is bobbling the ball.

What is the Tag Up Rule?

Closeup of a baserunner's foot standing on a base

In the sports of baseball, softball, and kickball, tagging up is a rule that forces baserunners to remain at their base until a fielder catches a fly ball. Once a fielder catches a fly ball, the runner must “tag up” by retouching the base they were at when the pitcher delivered the pitch.

The MLB rulebook defines the tag up rule as “He fails to retouch his base after a fair or foul ball is legally caught before he, or his base, is tagged by a fielder. He shall not be called out for failure to retouch his base after the first following pitch, or any play or attempted play. This is an appeal play” (Rule 5.09(b)(5))

In other words, the runner must retouch their base after a ball is caught. If they don’t return to their base, a fielder can appeal the play for an out.

However, the tag up rule does not apply to every single play. There are two conditions that need to be true before the tag up rule is in effect – when there are less than two outs and when a batted ball is caught by a fielder before it touches the ground.

Let’s dive deeper into why both of those scenarios must be true before baserunners need to tag up.

The Tag Up Rule is Enforced When There Are Less Than Two Outs and a Fielder Catches a Fly Ball

When you think about it, it makes sense that the tag up rule only applies to scenarios where there are less than two outs. The tag up rule only applies to batted balls that are hit in the air and if the defense catches the ball, the inning is over.

So the first thing that must be true is that there need to be less than two outs in the current inning. It never makes sense for a runner to tag up when there are two outs in the inning because one of two things will happen. Either the defense catches the ball for the third out and the inning is over, or the defense makes an error and the runner can advance.

In either of those scenarios above, tagging up does not give the runner any kind of advantage. The only thing a runner can hope for is the defense making an error, which means they’ll need to run anyway.

The second thing that must be true is a fielder needs to catch a fly ball or a line drive before it touches the ground. And one thing to note is that runners are able to leave their base once the ball makes contact with the fielder, not necessarily when the fielder catches the ball. This is a big distinction to make because sometimes a fielder will bobble the ball.

If the fielder bobbles the ball, the runner doesn’t have to wait for that fielder to catch the ball – that runner can just advance after the ball has made contact with the fielder.

In fact, there is a “Catch Comment” in Rule 5.09(a) of the official MLB Rulebook that states “Runners may leave their bases the instant the first fielder touches the ball”. This rule was put in place to prevent fielders from intentionally bobbling a fly ball to prevent runners from advancing.

What Happens if a Runner Doesn’t Tag Up?

Once we understand what the rule is, we also need to understand what happens if runners fail to follow that rule.

As a general rule, a runner who fails to properly tag up will be out if the defense appeals the play. However, the runner will be safe if the defense fails to appeal the play before the next play.

Let’s look at those two scenarios in more detail.

Defense Must Properly Appeal a Tag Up Play to Get an Out

For the defense properly appeal a tag up play, three things need to be true:

  • The ball needs to be live
  • The defense needs to make it obvious what they are appealing
  • The appeal needs to occur before another play is made

If all the above scenarios are true and the runner left before the ball touched the fielder, that runner is out. However, if the defense fails to make it obvious what they are appealing or another play is first made (like a pitch being delivered, a balk, or a bad throw that goes out of play during the appeal), then the umpire will not call the runner out.

Examples of a Live-Ball Appeal

The most common example of a live-ball appeal you’ll see is when the runner fails to tag up and the defense immediately throws the ball to the base before the runner can touch it. When this occurs, the defense earns a double play.

A lot of people associate this type of play with a force out, but is failure to tag up a force out?

While failure to tag up may look like a type of force out, failure to tag up is actually a live-ball appeal. In this scenario, the defense doesn’t need to speak to the umpire to let them know what they are appealing because their actions make it obvious what they are appealing.

Another common example of a live-ball appeal occurs after the play has ended and the runner has safely made it to the next base. Before the next play occurs, the defense will make sure the ball is live and then they will throw the ball to the base the runner failed to tag up. As long as the defense is obvious about what they are appealing, the umpire will call the runner out if that runner failed to tag up.

Runners Will be Safe if the Defense Fails to Properly Appeal

If the defense missed that a runner failed to tag up, the runner will be considered safe. The runner will also be considered safe if the defense makes a play before appealing. Some examples of a play would be throwing a pitch, balking, or throwing the ball out of play while trying to appeal.

Why is There a Tag Up Rule?

You may understand what the tag up rule is and how to use it, but the next question you might want to know is the “why” behind the rule. Why is there even a tag up rule?

The tag up rule is in place to prevent runners from having an unfair advantage of advancing bases while the ball is in the air. If the tag up rule did not exist, runners would very easily advance multiple bases while the batter hit a high pop-fly.

The tag up rule is also a way to reward the defense for making an out. If they catch the ball for an out, they are rewarded by forcing runners back to their base. If the tag up rule did not exist, then all that would happen is an out would be recorded and the runners would all be advancing regardless of what the fielder did.

When Should You Tag Up?

Youth baserunner in a red shirt is standing on second base and waiting for the pitch to be delivered

All baseball and softball players will find themselves in a situation where they are a baserunner and they need to decide if they should tag up or advance to the next base. If the fielder catches the ball, they need to tag up. However, if the fielder does not catch the ball then the runner will try to advance as many bases as possible. This leads a lot of players to wonder about when you should tag up.

As a general rule, players should tag up when a batted ball has a good chance of being caught and there are less than two outs. If a runner is unsure a batted ball will be caught, they should run halfway to the next base and watch to see if the ball is caught. With two outs, players should always run.

Another common scenario where you want to tag up is when a ball is hit deep into the outfield with less than two outs and the runner is on third base. Regardless of whether or not the outfielder has a chance to catch the ball, the runner will always tag in this scenario. Whether the outfielder catches it or not, the runner on third base has a great chance to score because of how far the outfielder will have to throw the ball.

Frequently Asked Questions About Tagging Up

Can you Advance on a Foul Ball?

Runners are only allowed to advance on a foul ball if the defense makes a catch. After the catch has been made, the runner needs to tag up by retouching their base. After tagging up, runners are free to advance at their own risk.

How Many Bases Can a Runner Advance During Tagging Up?

There are no limits to how many bases a runner can advance after tagging up. If runners are able to make it from first to home after tagging up, then the rules allow them to do that.

Can You Tag Up Before the Ball is Caught?

Runners are allowed to tag up by touching their base before the ball is caught. Once a fielder makes the catch, the runner is free to advance to the next base. If the fielder bobbles the ball, the runner can advance to the next base as soon as the fielder makes contact with the ball.

Why Do Baseball Players Not Tag Up When There are Two Outs?

Baseball players do not tag up when there are two outs because if a fielder catches the ball, the inning is over. If the fielder misses the ball, then the runner will need to advance. So there is no benefit to tagging up, there is only a potential benefit to running when there are two outs.

Do Runners Need to Tag Up on a Foul Tip?

Foul tips are treated as swinging strikes and runners do not need to tag up. However, if a catcher misses a foul tip then the play is ruled a foul ball.

Do Runners Need to Tag Up on an Infield Fly?

Runners are required to tag up on an infield fly. On an infield fly, the batter is already called out so runners are not forced to advance to the next base, but if runners want to advance to the next base they still need to properly tag up.

Steve Nelson

I'm the owner of Baseball Training World. I live in Denver, Colorado and I enjoy playing baseball on two different adult baseball teams in the surrounding area.

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