1. Create a box with follwing parameters.
= 
2. Now apply spherify modifier on it with 100% value, and convert it into editable poly.
3. By selecting the polygon selection select all the polygons, and apply inset with the following setting:
Our object now look like this .

4. With the same selection apply Extrude with these setting.

5. Now apply Turbosmooth modifier with Iteration 2, and our golf ball is ready .

You may also use Geospher in place of box for different ball shapes.