Thanks for the picture.

I suspect that this is caused by some type of fungal disease, Fortunately, many fungal turf issues only affect the grass foliage and not its roots. My guess is that if you were to rake up this brown grass and do nothing else, these areas would green up during the coming season. However if you are so inclined after raking, you could apply new grass seed to these areas. Have you seen brown areas like this in past springs or is this the first time you have observed them? Take a look at the following, looking at the various symptoms, and perhaps you might be able to determine the particular type of problem affecting your grass

https://fertilawnmn.com/turf-diseases/ - :~:text=Fusarium Blight is a turf,above 80) enhance symptom expression.

https://apps.extension.umn.edu/garden/diagnose/plant/turf/circular.html

https://www.bachmans.com/information/care-advice/common-lawn-problems

With respect to application of fungicides, they are most effective in preventing fungal spores from germinating and a lesser effect upon an actively growing fungal condition. Here is some information about the treatment of turf fungal diseases:

https://www.apsnet.org/edcenter/disimpactmngmnt/topc/Pages/Fungicides.aspx

In short, we should first try to narrow down the possibilities that might be causing these browned areas. I suspect either snow mold or brown patch at this point. These are the two most common turf fungal diseases seen at this time of the year.

https://www.jaredslawncare.com/identify-lawn-diseases

https://www.thespruce.com/brown-patch-lawn-disease-2153086

After looking at the above, please get back to me with your comments and thoughts. Thank you.

Thanks for the pics. Hopefully you received the response I sent yesterday (5/31/21). In trying to address your situation, it is critical to distinguish between a fungal infection and a singular event that might have occurred. My question:  have you seen this brown turf in previous years, especially in 2020?  If so, what did your turf look like in late August and early September? Brown grass spots in the spring that disappear as the season progresses is characteristic of fungal diseases.  These can be resolved over time with some effort.

On the other hand, if your yard looked good in 2020 as well as in previous seasons, this would signal a first-time event occurring between 2020 and 2021.

I do not want to make recommendations that would entail considerable effort on your part without having sufficient information at hand.

Thanks for your patience!