Louie Sanchez and Marvin Norwood, both of Rialto, Calif., originally were charged with one count each of mayhem, assault by means likely to produce great bodily injury and battery with serious bodily injury, all felonies. Both pleaded not guilty.
Sanchez and Norwood also are facing federal charges of being a felon in possession of firearms.
Stow, a father of two and a paramedic, was beaten in a parking lot after the 2011 Opening Day game between the Giants and Dodgers in Los Angeles. He suffered brain damage in the beating and spent two years in hospitals and rehabilitation centers before returning home this past June. He is permanently disabled, and his parents and home nurses provide around-the-clock care.
His family members are expected to make victim impact statements at Thursday's hearing, ABC7 reported.
The Associated Press contributed to this report.