A woman who suffered "serious injuries" at the hands of an as-yet unknown attacker has been released from the hospital, the San Francisco Police Department says.

SFPD spokesperson Officer Albie Esparza says that at around 5:50 Thursday night, following a game in which the Oakland A's prevailed against the SF Giants 6-1, officers were called to the Giants ballpark on reports of an aggravated assault.

Esparza says that just outside the stadium at 2nd and King Streets, two men got into a verbal altercation with a 28-year-old San Jose man and a 27-year-old Oakland woman, the latter of whom was wearing an Oakland A's cap. According to Esparza, one of the men punched the male half of the couple in the face. When the woman attempted to intervene, she was punched as well by the second suspect, hit her head on the sidewalk, and was knocked unconscious. The suspects fled the scene in a gold Toyota Tundra truck.

"When you're with your friends, you want to stop an attack or break up a fight," Esparza said at a press conference Friday morning. "That's human nature."

Witness Kristin Sauchak tells SFist that she had just left her office in the area when she saw "a woman in A's gear being loaded into a stretcher, and witnesses giving statements that a man attacked her and then got away in broad daylight."

"She was in poor shape," Sauchak tells SFist. Esparza says that the woman was transported to San Francisco General Hospital, but was released Friday morning.

The male victim. Esparza says, was treated at the scene for chipped teeth.

According to an email sent by Esparza early Friday morning, one suspect in the attack "was taken into custody by Sacramento Police last night."

At Friday morning's press conference, SFPD identified the arrested suspect as 32-year-old Sacramento man Francisco Lopez. He has been booked under one count of conspiracy and one count of assault with a deadly weapon.

Police were able to locate Lopez using the address associated with the registration of his truck, Esparza said.

At the press conference, police said that though the victims were in A's gear, they do not believe the altercation was related to any sort of team rivalry. In fact, police don't even know if the suspects attended the baseball game.

The search continues for the second suspect, described as a black male, 30 to 35 years old "with distinctive green or hazel eyes." According to Esparza, this second suspect is the man who struck the female victim. Esparza says that police are seeking video footage of the attack from surveillance cameras, in an attempt to better identify this second suspect.

As this is an open and active investigation, witness accounts are crucial. Esparza asks that anyone with information on this case contact SFPD anonymously at 415-575-4444 or to text-a-tip to TIP411 with SFPD at start of message.