Answer: I wish there were an easy answer, but brown areas in the lawn could be caused by dog urine, disease, drought or it may even be that the patch in question has cool season grasses which go dormant in the summer months (but green up again when the weather cools). What you might try is raking out the dead grass and reseeding the area. This should at least help it green up right away.
Best wishes with your lawn!
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