(CNN) -- One of the stars of MTV's "Jersey Shore" is facing an aggravated assault charge stemming from an incident in the reality show's first season, according to an indictment unsealed Friday in New Jersey.
Ronnie Ortiz, 25, is accused of knocking Stephen Izzo unconscious on September 4, 2009, in Seaside Heights, New Jersey, according to court records.
Ortiz faces up to five years in state prison if he is convicted of third-degree aggravated assault, according to Capt. Thomas Hayes of the Ocean County Prosecutor's Office.
Extensive efforts on both sides to reach a plea agreement forced the delay in charging Ortiz, Hayes said. No agreement was reached.
The grand jury handed up the indictment Thursday. A pre-arraignment conference on Ortiz's case is scheduled for January 4.