TMZ Sports broke the story ... a woman claims she was boozing and using marijuana with Masina in Utah on July 26th and passed out ... only to awake with the linebacker on top of her engaging in anal sex.
The woman says she woke up the next morning in pain and went to police, and a rape kit was administered.
Now, officials have hit Masina with 3 felonies -- 1 count of rape and 2 counts of forcible sodomy.
The woman claims Masina and his USC teammate Don Hill raped her during another incident in Los Angeles earlier in the month.