Judge Cena dropped the charge of rape of an intoxicated person after McDonald's accuser refused to testify.
"Despite my best efforts to convince the victim to testify, she refused," prosecutor Chris Lamiero said, per Tracey Kaplan of the Mercury News. "Regretfully, McDonald will not face a jury for what he did that night. We are disappointed that he will not be held responsible."
He was facing up to eight years in prison if convicted.
The woman had also sued McDonald in a civil court and received a settlement of over $100,000 as a result. She maintained that the settlement did not include a stipulation that she must drop the criminal charges, per Kaplan. Rather, in a statement she read to the court, she cited exhaustion and stress as reasons she needed to move past the case.
She said she slipped and fell on a pool deck at McDonald's San Jose residence during a party in Dec. 2014, per the AP's report. She said she continued to fall after due to a head injury and consuming alcohol, and that McDonald sexually assaulted her after carrying her to his bedroom.
Niners linebacker Ahmad Brooks has been charged with sexually battery of the same woman during the party and is still being tried.
McDonald, 33, hasn't played in the NFL for two years but may attempt a comeback.
"He has to put on 20 pounds and see if he can get back in the NFL," McDonald's attorney, John Halley, told Kaplan.
This article will be updated to provide more information on this story as it becomes available.