Thanks for contacting us about your lawn spots. This appears to be ascochyta leaf blight, common this time of year. This fungal disease is primarily a disease of the leaf, not the root or crown so bluegrass lawns rarely die from this disease. Controlling and reversing the damage is done primarily by good cultural practices (proper irrigation, not mowing when wet, collecting the clippings during outbreaks, avoid excessive nitrogen fertilization in spring, proper mow height and sharp mower blades). Because ascochyta leaf blight development is sporadic and rapid, fungicides are often ineffective due to being unable to treat it at the right time. See the following links for comprehensive information.

Ascochyta Leaf Blight: http://extension.colostate.edu/topic-areas/yard-garden/ascochyta-leaf-blight-of-turf-2-901/

Lawn Care: http://extension.colostate.edu/topic-areas/yard-garden/lawn-care-7-202/

Karin