Chinch bug patches are irregular in shape and these look somewhat circular to me, but it's easy enough to check for them. Just push an open-ended bucket or can into the turf at the edge of the problem area and then pour some water mixed with a squirt or two of dish soap (I use a couple of tablespoons per two gallon watering can) into the can and wait for them to float to the surface. Just pouring the solution onto turf without the can will bring up the adults in my experience but not sure about the nymphs.
Again the type of grass is a factor, as Jean's link says "Although it is a serious pest only on St. Augustinegrass lawns, the southern chinch bug occasionally may feed on zoysiagrass, centipedegrass, bahiagrass or bermudagrass."
