The boy's mother, Robie Lynn Jenkins, and her boyfriend, Tremayne J. Spillman, told investigators they were dog sitting a 12-week old Pit Bull after the dog's owner was arrested on a gun charge the night before.
They put the 4-month-old infant on a foldout couch in the living room while they slept on another couch nearby.
Jenkins said she was on medication and never heard the child cry out. She discovered the injury when she went to change the child's diaper.
The infant was taken to Pitt Memorial Hospital where doctors say his foot may have to be amputated.
Lt. Pam Sanders said investigators planned to issue felony child abuse warrants for Jenkins and Spillman Monday. The investigation continues.