The hard part of the rundown is catching the runner off base. Once that is accomplished, the rundown itself is simple. Few teams at the 11-12 year old level do it well.
Rundown Rules
Wait at the base for the ball to be thrown to you. By moving toward the runner, the fielder shortens the distance the runner has to go to be safe. Once the runner is by the fielder there is no defender between the runner and the safety of the base. Therefore the fielder chasing the runner must throw the ball much sooner and doesn’t have much chance of catching the runner.
The fielder waiting for the throw should be on the same side of the baseline as the “chaser.” This gives the chasing fielder a clear path to throw the ball to the fielder covering the base. If the fielder covering the base is right on the baseline, the runner will be in the way of the throw and make it difficult for the chaser to give a good throw to their teammate.
Once the fielder covering the base catches the throw, they should immediately start to run at the runner. They should hold the ball in their throwing hand above their shoulder ready to throw as they run. If they can catch the runner they should then reach to make a gentle tag. This not only prevents bruises and hard feelings but prevents a rough tag from knocking the ball out of the fielder’s hand.
The chaser should throw the ball when the runner has only one third of the way to go to get back to the base they left. If chasing toward the next base the throw should be made sooner because if you are going to “lose” the runner, you would rather lose them at the base furthest from home.
After making the throw, the former chaser should cover the base they threw the ball toward. They must take the place of the new chaser who is now running away from that base. This is the aspect of the rundown that is the most difficult for most players to master. Their impulse is to return to the base they were covering when they got the ball.
After throwing the ball the fielder must get out of the baseline to avoid interference on the runner.
The Pattern
The rundown is one of the most beautiful plays in baseball when done right. There are at least three defensive players involved: one player covering each of the bases the runner is between and one player holding the ball chasing the runner. The fielders alternate being the chaser. After chasing, each player covers the base they were chasing the runner toward.