Rice had been charged with simple assault after police said he knocked out Janay Palmer on Feb. 15 at the Revel Casino. But a grand jury indicted him Thursday on a more serious count of aggravated assault. It carries a three-to-five-year sentence.
Palmer also had been charged with simple assault. Prosecutors say that complaint was dismissed.
The couple lives in the Baltimore suburb of Reistertown.
Palmer's attorney has said he's certain no crime was committed. Rice's attorney, Michael Diamondstein, says Rice denies the charge and that the couple are happy and in counseling.
The Ravens issued a statement saying ''we know there is more to Ray Rice than this one incident.''