Yeah, tell Mother Nature to stop watering so much.
Seriously, I had a similar problem several years back. We had a neighbor up the hill from us who had just put in new sod and they were watering it way too much. The excess water was running down into my backyard and we ended up with brown patches like you are experiencing.
I was told it was a fungus caused by too much water. It was suggested that I go beat up my neighbor and use the granular version of Revive on my lawn. It worked, the brown spots disappeared in about a month and the neighbor cooled it with the water.