The San Joaquin County Sheriff's Office said inmate Corey Hughes, 27, slipped away from his work crew Monday.
Hughes was serving time for a weapons charge and was housed in the Honor Farm prison.
The impatient Hughes was scheduled for release in just a few months - February 6.
Hughes remained missing into Tuesday evening, but the search hasn't been fruitless for the sheriff - a tip led deputies to the home of 39-year-old Chad McDonald, a felon on searchable probation. While looking for Hughes, deputies found two firearms inside the home.
As a result, McDonald will be booked into the San Joaquin County Jail on weapons charges, the sheriff's office said.