The postponement gives prosecutors more time to review videotape given to them by the woman who originally accused Foster of domestic violence before she recanted her story.
Foster was present at a San Jose courtroom before his plea hearing was rescheduled.
Stephanie Rickard, the attorney for 28-year-old Elissa Ennis, said in a statement last week her client initially lied to police and the NFL team about a violent incident at his home in Los Gatos, Calif.
Rickard said the injuries, including a ruptured eardrum, that sent her client to the hospital, were suffered in a fight with another woman. She also claimed there is a video of that confrontation to back her up.
"[Foster] did not strike her, injure her or threaten her," Rickard said in a statement.
The statement claims that Ennis' injuries "were the result of a physical fight with another woman, and that Foster tried to end his relationship with Ennis after he learned of the fight.
"She was extremely upset and told him if he broke up with her she would 'trash his career,'" Rickard said.
Officials said Foster dragged the woman by her hair, physically threw her out of the house, and punched her in the head eight to 10 times. Prosecutors officially charged Foster on April 12 with felony domestic violence, another felony for forcefully attempting to prevent the victim from reporting the crime, and a third felony for possessing an assault weapon.
The Sacramento Bee cited the Santa Clara County District Attorney's Office as saying that the woman flagged down a passing car after the incident and suspected she would not cooperate with the investigation. They continued the case without her help.
Reported evidence includes the 911 call on the day of the incident, the medical report from the hospital and any photographs that police took. The district attorney's office also could call upon the motorist who helped the girlfriend as a witness.
49ers general manager John Lynch said the team is prepared to release Foster if the charges are proven to be true.
Foster is also subject to possible NFL discipline under the league's personal conduct policy. The league mandates a six-game suspension for a first-time domestic violence offense.
Foster started all 10 games in which he played last season as a rookie.