Rubbing/Grinding Noise in the front driver side wheel

I have a 2000 Ford F-250 4x4 with the 7.3 diesel and 98k miles. I have started noticing a rubbing/grinding noise in the front driver side wheel. It started about a week ago but at the time it was minor and did not occur very often. However, I was headed to work this morning and it seemed to be almost constant. I have heard several different theories as to what this could be. I am not sure if it is related to my brakes or if it is a problem with my wheel bearing.

Any help would be greatly appreciated.
Thanks