MLB baseballs used for Opening Day this season. But the committee of 10 scientists MLB assembled to conduct a study into this power surge couldn’t answer one crucial question: What changed? MLB’s study concluded that the balls have become more aerodynamic, flying farther through the air with less resistance. That isn’t due to any meaningful difference in the size, weight or seam height of the balls. A visit to the plant in Costa Rica where baseballs are made was fruitless.