Valdez is charged with second degree murder and felony child abuse.
The three-year-old was taken to Children's Mercy Hospital in Kansas after he suffered brain injuries, facial bruising and a laceration at his home at 1502 S. Michigan Avenue November 10. He died two days later.
The probable cause statement indicates Valdez was the only person supervising the boy at the time the injuries occurred.
The boy died 22 days after the Joplin Police Department arrested Valdez for domestic assault at the same address, 1502 S. Michigan Avenue, where police say the child abuse took place. The victim was the boy's mother, Natasha Michelle Bilbrey, 22, according to the JPD incident report.
Valdez' trial is scheduled to begin June 3.