If you’re watching a baseball game, you will eventually hear an announcer say or a coach yell the phrase Tag Up. But what does that mean exactly?
What Does It Mean to Tag Up?
Tagging up is any time when a runner attempts to advance on a flyball out, and it requires the runner to wait until the ball has -xz[ed a fielder’s glove before attempting to advance.
Tagging up on a flyball can lead to a run if a player scores from third base (or even second base on rare occasions). This is known as a sacrifice fly, and gives the batter an RBI and the runner a run scored.
If a player leaves the base too early, it is up to the defense to recognize this has happened. They can then tag the base from which the runner left early in order to “double the player off”, which is another way of saying: put out a runner who left base too early on flyball out.
In doing this, the defense is appealing to the umpires to rule the player out. If the umpires agree, then the player is considered out and all actions by that player subsequent to leaving base (e.g., scoring a run) are negated. However, this is considered a time play and not a force out. So, if any runners scoring prior to the player being doubled off still count.
When Can a Tagged Up Runner Leave the Base?
Just like the rule states: as soon as the ball touches a player. This requires special emphasis because many, perhaps most, people believe a runner cannot leave the base until the ball is caught. If this were true, though, then the defense could technically attempt to keep bubbling the ball in order to get closer to the infield in order to prevent a player from advancing.
For an example of this in action, here is a play where Chase Utley demonstrates his full knowledge of the rules:
When to Stay, and When to Go?
One of the biggest concerns of a baserunner on a flyball is whether to stay on base in order to tag up or go halfway down the baseline to the next base in anticipation of the ball dropping. Better baserunners get a feel for when balls will drop. And basecoaches should also be guiding runners as to when to stay on base to tag up.
Antonelli Baseball has a short video to go over some of the guidelines: