Sgt. Sanford Rosenberg says two men in Dodgers clothing followed three men in Giants gear as they walked to their car after Thursday night's 2-1 Dodger victory.
Rosenberg says the attackers yelled slurs against the Giants and began kicking and punching the men.
One victim suffered a head injury and was hospitalized in critical but stable condition.
Rosenberg says the injury is not life-threatening.
Investigators don't have the identities of the suspects and are asking anyone with information on the attack to call police.