Officials say Zito's car was broad-sided at Sunset Boulevard and Sunset Plaza Drive just before 8 p.m., and he was not at fault.
Zito was taken to Cedars-Sinai Medical Center for observation and was released. On Thursday, Zito was scheduled to have more tests following the accident.
According to a Giants spokesman, Zito has soreness in his neck and upper body.
The other driver was not injured, and it's not yet known if that driver will be cited.
The Giants were in Los Angeles to play the Los Angeles Dodgers on Thursday for opening day in baseball. Zito, a former Cy Young winner and the team's No. 4 starter, had been expected to pitch over the weekend.
The Associated Press contributed to this story.