Tag up
IN BASEBALL, ACTION OF A RUNNER TOUCHING THEIR STARTING BASE AFTER THE BALL LANDS IN FAIR TERRITORY OR IS TOUCHED BY A FIELDER
Tagging up; Doubled off; Doubling off; Doubling up
In baseball, to tag up is for a baserunner to retouch or remain on their starting base (the time-of-pitch base) until (after) the ball is first touched by a fielder. By rule, baserunners must tag up when a hit ball is caught before it bounces by a fielder, and in such situations, are out if any fielder with possession of the ball touches their starting base before they do.