The Middlesboro four month old was rushed to East Tennessee Children's Hospital after suffering both internal and external injuries.
Two people now face abuse charges, including the boy's mother.
A preliminary investigation led police to Randy J. Vaughn, 23, of Middlesboro.
Police say Vaughn lived in the home with the baby but he's not the father.
Police the infants mother, Christina Terrell, 19, is also facing 2nd degree criminal abuse charges.
We're told the baby is now in stable condition and may be taken out of intensive care on Friday.
Authorities are not ruling out the possibility that others may have played a role in the abuse.
They also say charges could be upgraded against the two suspects.