Defensive indifference is a term used in baseball to describe a situation in which a base runner is allowed to advance to the next base without any attempt to throw him out by the defense. This most commonly occurs when a team is comfortably ahead in the late innings of a game and the defense decides that it is not worth the effort to try to throw out a runner attempting to steal a base.
For example, if a team is leading by six runs in the bottom of the eighth inning and the opposing team’s leadoff batter gets a single, the defense might decide not to attempt to throw out the runner if he tries to steal second base. This is because the team with the lead is more concerned with preventing the batter from getting on base than with preventing the runner from advancing to second base.
In this situation, the official scorer will usually record the runner’s advance as “defensive indifference” rather than as a stolen base, since the defense did not make any effort to throw him out.