I would agree that if you son is really into baseball, this may be something he would want to do.
As the mom of a softball player, who is much older, if they are really committed, they start that young. As part of a club or premier team, she played many times in tournaments that were over holidays. We were thrilled that she had a passion and took her commitment seriously. Shoot, my husband and I paid to attend our school's gala one year then found out we had a softball tournament. After spending the entire day at the fields and driving over and hour to get home, we slid into the auction, windblown, sunburnt and still in our sweats, just in time for the live auction!
Our school hosts a varsity soccer tournament every year that ends on the Saturday of Labor Day in the fall.
My point is that as the kids get older, you may have to make some difficult decisions. I'm NOT saying that the kids call the shots, but if a commitment is made it's honored.