Ryan White was hit by a pickup truck as he and his family walked in a crosswalk a few blocks from AT&T Park after a game between the Phillies and the San Francisco Giants Thursday night.
At the request of the family, hospital officials are not releasing details about the boy's injuries.
Police say after Ryan was hit, the driver of the pickup truck, Andrew Alan Vargas, collided with several parked cars. A 58-year-old Granite Bay woman was also hit by the truck, but was not seriously injured.
About an hour after Ryan was hit, the 21-one-year-old Vargas was arrested in Hayward on suspicion of drunk driving and felony hit-and-run.
He was being held in San Francisco County Jail.