The hearing for Louie Sanchez, 30, and Marvin Norwood, 31, is expected to last four days.
In the morning, the prosecution played a videotape of Norwood during a three-hour police interrogation. It showed Norwood sitting next to a police detective. At one point, Norwood uses the detective's cellphone to call his mother.
"I got arrested for that Dodger Stadium thing, so there's really not that much I can say over the phone, but I mean, I was involved," Norwood can be heard saying. "Yeah, I was. I mean to a certain extent I was, but whatever. All right. Well, you know where I'm at. I'm sorry."
During cross-examination, the defense said Norwood and Sanchez may have been involved in an incident after the game, but not the attack on Stow.
Several witnesses were also called to described the actions of the suspects on Opening Day, when the beating took place.
One witness, Marc Lu, was at the game sitting with friends who wore the Giants' colors, orange and black. He said the suspects harassed them.
"Throughout the game we were getting pelted with peanuts, and then at the end of the game as soon as the game ended, one of the guys picked up a Coke bottle and sprayed it," Lu said. "It looked like he was, I would say, ready to fight. He was facing us, kind of staring us down."
During the hearing, 22 witnesses and several police will be called by the prosecution to testify and a judge will decide if there is enough evidence to move forward with the trial. The defense won't call any witnesses during the hearing.
The witnesses include some of Stow's friends who were with him the night he was attacked, and Sanchez's sister, Dorene. She is considered the main witness in the case and will be one of the last people to testify.
According to police, Dorene Sanchez drove her brother and Norwood from the game the night of the attack, but she has not been charged. Her testimony is expected to take an entire day. Louie Sanchez's parents and grandparents were present at Wednesday's hearing.
Both men have each been charged with mayhem, assault by means likely to produce great bodily injury and battery with serious bodily injury.
Stow was attacked last opening day at Dodger Stadium while wearing a Giants jersey. He was attacked in the parking lot following the game. According to court documents, the prosecution claims Norwood and Louie Sanchez shoved Stow, followed him, then punched him in the side of the head and kicked him in the side of the head after knocking him unconscious.
Stow suffered head trauma and is still recovering from injuries. A support website for Stow says he now suffers from short-term memory loss and still doesn't understand or realize what has happened to him.
The trial will be held in a downtown Los Angeles criminal court, but the two will face a separate trial in federal court after investigators found the two allegedly possessed weapons illegally. Officials said numerous guns were found hidden in the attic of Norwood's home.
Both have pleaded not guilty to the charges. Louie Sanchez's lawyer said his client may have been mistakenly identified, as was the case of initial beating suspect Giovanni Ramirez. Both men could face a maximum of 10 years in prison if they are convicted of the charges.