Without a picture of the damage we can’t make an accurate diagnosis.  Raccoons or skinks are likely suspects especially since the sod is lifted and rolled.   They would be looking to eat the grubs.  Other critters can also do damage but usually you will see holes and/or digging.  The likely reason is grubs for any of the critters.  Grubs themselves by killing the grass roots can do this kind of damage without any critter involvement.  
Regardless the solution-getting rid of the grubs- is the same.  The grubs have likely burrowed deeply into the lawn by now so the next opportunity to treat the grass will be May to early June when the adult beetles first emerge and start laying eggs (mid-June to mid-July in Minnesota). Chlorantraniliprole (such as Scott's Grub-Ex) is an effective, preventative insecticide that is also low risk to bees.
See the website for for more information:
 https://extension.umn.edu/garden-and-home/yard-and-garden/yard-and-garden-insects/japanese-beetles