Officers responded at about 12:50 a.m. to a report of a shooting at a house party in the 900 block of Morgan Street, where a mass of people fled when police arrived, according to the Police Department.
A preliminary investigation revealed the victim showed up with unwanted guests and was asked to leave, which escalated to a shooting, police said.
The victim underwent surgery and is expected to survive.
Police believe the suspect might be affiliated with a local street gang.
Anyone with information is asked to call the Police Department's gang crimes investigations unit at (707) 543-3670.