The ball is low poly and has not been subdivided.
But, maybe that’s your goal as a developer.
But I don’t think adding slightly more vertices will slow down the game.
Agree with FedPete. Add subdivisions and it will look way batter 
. Plus if you really want to keep poly count low - manually increase detail only in the area around the holes. LoopTools addon might be helpful there as it has nice ‘circle’ function (or use To Sphere command after adding some more detail to get the circle right)
Thank you for your feedback, and that is good to know the number of vertices in proportion to game performance. I will keep that in mind in future development.
For this section I decided to keep the bowling ball as a low poly model since the goal was keeping the triangle count under 1000, and I was already at 412 before subdividing.
Thank you for the suggestion . Adjusting around the areas that need detail will help in future projects.