Help with stressed areas on zoysia lawn

[rrmears]

I live in North Alabama and as my zorro zoysia lawn emerges from dormancy, I noticed 3 areas where the lawn exhibits a possible problem. I have attached a photo illustrating one of the areas and was looking for advice on how to investigate what might be happening. Other than an application of pre-emergent late last fall and digging out the wild onions, nothing else has been applied to the lawn since it went dormant.