It looks like the result of compaction, say from mower path, and saturated soil. If the soil is compacted, it will not drain and water will stand on the surface. The combined effect will lead to anaerobic soil conditions which will inhibit root growth and hurt plants. The visible soil surface looks smooth, as if it was the bottom of a puddle.
I'd start by addressing compaction. Use a core aerator to remove plugs of soil and open up the soil. Depending on the results of a soil test I'd also consider adding dolomite or lime which can help percolation in clayey soils. I'd also let the grass grow longer - cut no lower than 3". This will improve root mass, which will in turn reduce compaction and improve drainage.
Finally, keep an eye on the area after irrigating or rain and cut back the water in those areas. Leaving the grass longer will help reduce the need for as much irrigation anyway.