Troy Fox with the Texas Board of Pardons and Paroles says Valencia had a limited criminal history and a "satisfactory institutional adjustment."
Law professor Marci Hamilton says releasing Valencia early is "just wrong."
Valencia was convicted of bodily injury to a child. Records show that Saul Castillo, who was 2 months old when he died, weighed less than his birth weight of nearly 6 pounds. Valencia could not immediately be reached for comment.
The father, who faces neglect charges, remains at large. The baby's siblings are in state custody.