I have been noticing my lawn has been yellowing in some areas. I looked
closer today and noticed the grass blades are yellowing and have dark
brown spots. Some blades are just yellow and some have yellowing with
spots. The spots are about the size of a pin head maybe bigger. I
looked closer and the spots seems to be like bumps.

Is this leaf spot or...?

I have looked in my lawn book and on the net for similar picturtes, but
nothing real close. The closest I have seen in my book is Leaf Spots.