Marin Catholic High School was playing against Justin-Siena High School at AT&T Park. It was off to an emotional start at Gunnar threw out the first pitch for the game.
His father, Bjorn Sandberg, thought maybe they could just come to the park and watch the game, but never get back on the mound.
Earlier this year, after Gunnar suffered a serious skull fracture, he was in a medically induced coma, and came out of it. Gunnar also just returned home two days ago from a rehab center.
Bjorn says his son's progress has really been remarkable.
"The therapy staff at the hospital, when they caught wind that this was going to happen, they ratcheted his workouts a little bit to make sure he would be ready for this and in his mind, there was never a doubt," said Bjorn.
"I think mentally, he was starting to prepare for this date even before we knew that he was mentally preparing for this day," said Lisa Sandberg, Gunnar's mother.
"I usually don't get choked up over things, but that was pretty special," said Bjorn.
What also made the day special was watching the support in ticket sales and t-shirt sales from friends and others to help Gunnar's medial fund.
The State Senate is going to consider banning metal bats in schools.
The best thing was to see Gunnar so physical on the mound and the smile on his face.