According to the San Jose Mercury News, Miller, 27, was convicted of disturbing the peace in a domestic-violence court in Santa Clara after he allegedly broke his fiancé's cell phone in a dispute. He was initially charged with vandalism in early May.
"The 49ers organization is aware of today's proceedings involving Bruce Miller," 49ers general manager Trent Baalke wrote in a statement. "Bruce knows what we expect of him as a member of this team and he has committed to taking the necessary steps to grow from this experience."
In a press release issued May 4, the Santa Clara District Attorney wrote, "While original reports indicated that Miller may have pushed his girlfriend from his parked car, an investigation into the alleged assault was inconclusive."
The night of the incident, police responded to a phone call from Miller's fiancé, who made the call from a witness' phone, and said Miller had pushed her out of a vehicle, took her phone and smashed it. She refused medical attention and did not sustain visible injuries or complain of pain, according to the press release.
Miller must attend a 16-week domestic-violence counseling course as apart of his plea agreement, that also stipulates he cannot make any contact with the victim until he is sentenced following the completion of the course. Miller and the victim are no longer engaged.
"We are satisfied that Mr. Miller is taking steps to address his underlying anger issues," Deputy District Attorney Tyrone Wilson told the Mercury News. "He will hear in his mandated class that domestic violence is unacceptable no matter what the degree or circumstance."
Miller has not taken part in the 49ers' voluntary offseason program over the last several weeks while he has dealt with this legal matter. The mandatory OTA session will take place June 9-11, and Miller is expected to rejoin the team shortly, according to a report from the Sacramento Bee.
The NFL, under increased scrutiny regarding its handling of similar cases, is likely to discipline Miller in the form of a suspension. Cowboys defensive lineman Greg Hardy was suspended 10 games this offseason after he was initially convicted of domestic violence in North Carolina as a member of the Panthers.
The league suspended Hardy without pay, despite his legal case in February getting thrown out, after conducting its own two-month investigation into the allegations.
In December, the 49ers released defensive lineman Ray McDonald after his second arrest involving a domestic violence allegation since the previous August. And after signing with the Chicago Bears this offseason, he was released again last month following another arrest under similar charges.
Miller has appeared in 61 games for the 49ers since getting drafted in the seventh round (211th overall) in 2011 out of Central Florida. He played along the defensive line in college before transitioning to fullback in the pros, where he became a key contributor in the team's run-heavy offense.
The only other fullback on San Francisco's 90-man offseason roster is Trey Millard (6-2, 247), who missed his entire rookie season in 2014 recovering from an ACL tear sustained while with Oklahoma. Millard has been a regular attendee of the team's offseason program this spring.