49ers Star Ahmad Brooks -- Pleads Not Guilty ... In Sexual Battery Case

San Francisco 49ers star linebacker Ahmad Brooks has pled not guilty to sexual battery ... stemming from a 2014 incident where he allegedly groped an unconscious woman.

The 31-year-old was NOT present in the Santa Clara courtroom when his lawyer entered his plea ... roughly one month after he was charged with the crime.

As we previously reported, the alleged victim claims the incident went down on December 14, 2014 ... after she met 49ers player Ray McDonald at a bar and went back to his home.

While at McDonald's place, the woman claims she fell and hit her head near the swimming pool ... and Brooks groped her in a sexual manner while she was unconscious.

She also claims McDonald raped her later that night ... and alleges surveillance footage from the home will help prove she's telling the truth.

If convicted, Brooks faces up to 6 months behind bars.