"It was not moving. Its eyes were closed. I thought, 'Lord, don't let this thing be hurt,'" he said.
When Prater picked the carrier up and put it in his van, the baby opened his eyes.
"There's a baby here in a carrier," Prater told the dispatcher over the phone.
Officers found a Social Security card, cash and a birth certificate with the baby.
It was 91 degrees when the infant was found, but police said it's unlikely the baby was on the side of the road for more than 30 minutes.
The baby was in good health and taken to a local hospital for an evaluation.
Family members helped located the baby's mother, who was also evaluated at a local hospital.
No names were released in the incident. A spokesman for the Oklahoma City Police Department said charges will likely not be filed.