Stealing vs. Pickoff in Baseball: Understanding Base Running Strategy

Question
Hi,

What is the difference between caught stealing or getting picked off?

Why would a runner with a lead go back to the base when the pitcher steps off the rubber?  

Answer
Caught stealing would refer to a runner being tagged out in an attempt to steal 2nd, 3rd, or home.  Picked off would refer to a runner being tagged out trying to return to the base that they currently occupy.

A runner with a lead would return to the previous base in an attempt not to be tagged out, as it is closer than the next base.

Thanks,

Pat