So baseball has these rules so the pitcher can't deceive the runner or batter. The game is so reliant on timing that it's unfair if the pitcher could try and trick someone. So there are a series of rules you have to follow otherwise it falls under "deception" (whether you mean for it to or not). When a pitcher doesn't follow those rules, it's a balk. So one rule, for example, says that you can't pitch unless your foot is on the rubber. If you're off the rubber, you can do whatever because you technically can't throw a pitch. You could flail your arms or do a jumping jack. But the moment you step your foot on the rubber, the rules take effect. If you suddenly wave your arms, that's a balk. If you step off and wave your arms, that's fine. Once you've taken the rubber, the next step is to either step off or come set. Coming set is when the pitcher brings their hands together, usually at chest level. You have to pause. You can't go foot on the rubber and then suddenly throw the ball. That's deception. So it's foot on rubber. Come set. Once you come set, you can hold there as long as you want. You don't have to immediately pitch. Usually it's annoying if you do that but you can. Your own teammates will yell at you if your pace is too slow. Once you're set, your next motion is a step off or the pitch. Once you start that motion, you have to complete it. If you suddenly stop, it's a balk. If you suddenly decide you don't want to pitch but want to pick off the runner, it's a balk. You can't use the motion to throw off the timing of the batter or runner. So in this case with Wisler, it's a balk because he had his foot on the rubber and made a motion with his hand. That didn't lead to step off, pick off, or coming set. So it's a balk. If he had stepped off and made the same motion, he'd have been fine.
