RULES IN BRIEF If a batter hits a foul ball, it counts as a strike against him until he has two strikes If the batter hits a foul tip on the third strike and the catcher catches it, the batter is ruled out on a strikeout Once a fielder catches a ball hit in the air, baserunners may leave their bases and try to advance to the next base before being tagged out with the ball If a baserunner strays from his base before a ball hit in the air is caught, the baserunner will be out if a fielder can get the ball and step on the base before the baserunner returns The batter may run past first base in a straight line and will not be declared out if he turns toward foul territory when he stops (to show he is not trying to advance to another base). However, the batter or baserunner can be tagged out with the ball if he runs or slides past second or third base A baserunner may try to advance to a base on his own, or steal a base, at any time the ball is in play but has not been hit by the batter The batter is allowed to go to first base if the umpire rules that the catcher interfered with his swing. This usually happens while trying to catch the pitch