The incident took place in the bottom of the ninth inning, when the bat slipped out of the hands of Hector Sanchez.
Per Todd Strain of KNSD, the fan was walking and alert when she left the stadium, although she needed a bandage on her head.
According to Troy Hirsch of Fox 5, there was a 15-minute delay in the game while medical staff helped the woman.
Meanwhile, a different fan was arrested during the incident after refusing to move to accommodate the staff, per Kirk D. Kenney of the San Diego Union-Tribune.
Sanchez fouled out to end the at-bat and the Padres eventually lost 3-2 in 11 innings.