Applying a gradient color without a form

Imagine a whant to do a spinning sphere. To do that I use a normal Oval form but then i whant to apply a gradient that goes from the inside left to the inside rigth of the sphere…ok!
To have the effect i aplly a tweening motion to the gradient ( and an APLHA increasing and decreasing gradient)… it´s like the reflection of a ligth that goes from left to rigth on the sphere.
The problem is:

i only can aplly a gradient color ( this gradient is like a ligth) to a form ( is that true?)
if so, when the gradient appear all is movement , the borders of the form were the gradient exist will be over the inside of the sfere , and that gives me a image (were the gradient is) over the sphere!!! (like 2 different images one over the other)

Is there a way to aplly just a gradient ( without a form ) witch can be like smood ON the sphere while it´s in motion, and giving us the inpression that the sphere is speening?

Thanks