These issues happen frequently and coaches tend tone very accommodating when one parent refuses to participate. I would suggest you speak with the coach and explain the situation, my guess is that accommodations will be made for the dates the child misses during Dad's time. Additionally, I am of the opinion that the Court is likely to do very little because of the age of the child. However, if the child continues to excel and shows promise of future endeavors, college scholarships for example, most can be receptive . It is about timing and I don't think it is right. When it is, you can file a Motion to address it with the Court.
I agree with Ms. Roberts. It's unfortunate, but a legal custodian can certainly throw a wrench in the works by their stubbornness. The coaches can be accommodating, but more importantly, he needs the game experiences as much or more than the practices. This is going to be a tough sell with the court, however, in that they are not likely to view T-ball as a necessary part of a child's life, at least not sufficient to order Dad to do something Dad doesn't think is worthwhile. So I'd sit with an attorney who can look at all the facts, especially looking at patterns outside of baseball that indicate Dad's not looking after the child's interests. If you can demonstrate an overall pattern, you have a much better chance at getting the judge's attention.
If your case is based in Northern Nevada, the advice my colleagues have provided is absolutely correct. There is no way the courts will put T-ball or little league over time with a parent. Your son's coaches WILL understand. And your ex is only shooting himself in the foot for being an ass, because your son is going to know that mom supports an activity he enjoys, and dad doesn't. When his friends ask where he was and why he missed a practice or game, he is only going to have his father to blame. Make very sure that you never say anything negative about your son's father in the presence of your child or where he could possibly hear you. If your son asks why dad won't let him play, simply tell him that is something he will have to ask his father because you cannot explain it. And start saving money for an attorney, because this will likely get worse, and you will probably need to address it in the court system in the future.
Responses are for general information purposes only, and are based on the extremely limited facts given. A consultation with an attorney experienced in the area of law(s) indicated in the question is highly recommended. Information and advice given here should not be relied upon for any final action or decision, as the information is limited by its nature to the question asked and the fact(s) presented in that question. THIS RESPONSE DOES NOT CREATE AN ATTORNEY/CLIENT RELATIONSHIP, particularly considering that the names of the parties are unknown.