Worn out patches in your lawn are definitely unsightly but they can also be confusing. There’s many reasons they can occur and determining the reason will help to fix it and/or stop it happening again.
Once you’ve determined the cause you can help the lawn repair itself but clearing out the bare/worn out patch, fertilising and giving it room and time to self-repair. Of course, if the worn out patch is cause by pests or disease then you’ll need to apply an appropriate insecticide or treatment first. Temporary fencing off the area from the pets and kids is a good idea too.