You probably have annual bluegrass. Dig up those areas and replace them with sod or seed for a grass that matches the rest of the lawn. Keep an eye on your drip irrigation system. Sometimes heads will get plugged with debris and plants won't get the water they need. Automatic timers are great tools, but your eyes are better when it comes to seeing if plants appear stressed for water.
Plants are thirsty.
A mistaken idea some people have is that if plants are drip irrigated, they need less water. The water savings comes from irrigating specific areas rather than unplanted surroundings. Cutworms munch right through tender seedlings at ground level. To prevent this, push a paper or foil collar firmly into the soil around the base of the plant. Or just put a toothpick snug alongside the stem.