Balks Caused by the Catcher [Official Rule 6.02(a)(12)]
There is no such language in the rule book as a “catcher’s balk.” The pitcher is charged with a balk in two situations created by the actions of the catcher: (1) If, when giving an intentional walk, the pitcher pitches when the catcher is not in the catcher’s box (this rule is seldom, if ever, enforced) and (2), if, with a runner on third base trying to score by means of a squeeze play or a steal of home, the catcher steps on or in front of home plate without possession of the ball, or touches the batter or his bat, the pitcher shall be charged with a balk and the batter awarded first base. No. 2 is covered in rule 6.01 (g).
Sometimes an eager catcher will leave his position and interfere with the batter trying to hit a pitch. A play like this happened June 4, 2016 when the Indians hosted the Royals. This detailed Insider Report will help you understand the “catcher’s balk” rule.
Did Yogi Berra commit a “catcher’s balk?”
Balks Caused by Batter: [Official Rule 5.04(b)(2)]
If the pitcher has started his windup or has come to a set position, but he does not go through with his pitch because the batter has stepped out of the box, it is not a balk.