Tag Up
Also known as: tagging, retouching, sacrifice fly advance
Tagging up means a baserunner returns to and touches their current base as a fly ball is caught, then takes off toward the next base — the legal method of advancing on a caught fly.
When a fly ball is hit, baserunners must wait at their base (touching it) until the ball is caught. The moment the outfielder touches the ball, they may advance. Elite taggers watch the outfielder's eyes and body language while keeping a foot on the base, then explode the instant the ball contacts the glove. On sacrifice flies from the outfield, runners at third should almost always tag up. On shallow flies, the depth of the outfielder. The runner's speed, and the arm strength of the outfielder all factor into whether tagging up gains an extra base.
Position your foot on the inside corner of the bag — closest to the base you are advancing toward — before the pitch is delivered, so that when a fly ball is hit you are already in the optimal push-off position without needing to reposition.
Practice watching the ball into the outfielder's glove from a tagged-up position specifically by having a partner track fly balls in the outfield while you stand with your foot on the bag and call "catch!" the instant you see glove-ball contact — this trains the precise timing discipline that separates tag-up masters from average baserunners.
Example
He tagged from third on a medium-deep fly to centre and scored easily. His read of the outfielder's positioning told him the throw would be too late.
How it shows up on video
On video, tag-up quality is measured by the runner's foot position on the bag at the moment of catch, the direction the body is facing, and the explosiveness of the first step off the bag. Common errors include the runner having both feet flat on the ground rather than positioned on the bag in a ready-to-push stance, the body facing the outfield rather than angled toward the next base, and the runner losing contact with the bag for an instant before the catch — which creates a retouch obligation that negates the advance.
Common mistakes
- Leaving the bag too early before the ball is caught — even a tenth-of-a-second early departure is a legal violation that results in an out if appealed by the defense
- Standing flat against the center of the bag rather than on the inside corner with the body angled toward the next base, losing the push-off position advantage that fast taggers use to gain an extra step
- Making the tag-up decision based on the depth of the fly ball alone without considering the outfielder's arm strength, throwing angle, and the presence or absence of a cut-off play
- Not watching the ball all the way into the outfielder's glove. This prevents precise timing of the departure — watching the fielder's glove make contact is the signal that must be seen before the departure step
In SwingVantage Motion Lab
Motion Lab does not analyze baserunning and does not see the catch or the bag, so it cannot time your tag-up.
Related terms
- Baserunning ReadA baserunning read is the split-second decision a runner makes based on what the ball does after contact — whether to advance, hold, or retreat.
- SlideA slide is the controlled fall a baserunner uses to reach a base beneath a tag, to kill momentum at the bag, or to avoid a collision with the fielder covering it.
- Secondary LeadThe secondary lead is the movement a baserunner takes as the pitch crosses the plate. A walking step or shuffle that adds momentum toward the next base the moment contact is made.
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