"It's a dream come true," said his mom, Ann Stow.
Stow suffered severe brain damage in the beating and for a time his prospects for any significant recovery were dim.
But on Thursday night, he walked onto the field using a walker and with a smile on his face and a wave to the crowd tossed the ball toward home to start the minor league San Jose Giants home opener against the Bakersfield Blaze.
Hours before the toss, Stow talked with KTVU Fox 2 about his upcoming appearance.
"I would like to throw it overhand, but that's going to come in some time," he added.
Dave Stow said his son's recovery has been slow, but heartwarming.
"Four years ago he couldn't even open his eyes," he said. "Now he's throwing a baseball."
Stow says he will continue to work hard on his recovery.
"First pitch now, could be more later," said Stow, "I'm ready for it."