Updated

Three more North Carolina defensive starters are not traveling with the team for Saturday's game in Atlanta against LSU, meaning the 18th-ranked Tar Heels could be without 15 players amid an ongoing NCAA investigation.

School spokesman Kevin Best said that linebackers Quan Sturdivant and Bruce Carter, and safety Deunta Williams weren't on the team plane as the Tar Heels prepared to leave Friday morning for Atlanta.

North Carolina had already identified 12 players — including NFL prospects Marvin Austin, Robert Quinn and Kendric Burney — that would miss the game as the NCAA looks into agent-related benefits and potential academic misconduct involving a tutor.

The school had said three unidentified players were still in jeopardy of missing the game against the 21st-ranked Tigers and wouldn't travel with the team when it left Chapel Hill, though it was working with the NCAA to determine their status for the game.

Best wouldn't say whether Sturdivant, Carter and Williams were the three players whose status is in doubt.

The school said in a news release that it had declared Austin, Quinn, Burney, cornerback Charles Brown, defensive end Michael McAdoo and receiver Greg Little ineligible "for violating school and/or NCAA rules." Another six players — top tailbacks Shaun Draughn and Ryan Houston; safeties Brian Gupton, Da'Norris Searcy and Jonathan Smith; and defensive end Linwan Euwell — are being held out of the game during the investigation.

"We are disappointed the players' choices have denied them the opportunity to compete alongside their teammates and represent the University of North Carolina," coach Butch Davis said in a statement. "Our coaches and players have a tremendous challenge this weekend, and despite these circumstances, our team will be excited to face LSU."

It's unclear how many games Quinn, McAdoo, Burney, Brown, Little and Austin will miss, though the announcement is a massive blow for a program that entered Davis' fourth season in position to contend for an Atlantic Coast Conference championship. The optimism had built since January when Austin, Little, Burney, Sturdivant, Carter and Williams all announced they would return to school for their senior seasons instead of entering the NFL draft.

Little is the team's top receiver, while the rest of that group joined Quinn — a junior widely considered to be a high first-round pick — on a defense that returned nine starters from a unit that ranked among the nation's best last season.

The NCAA first visited the campus in July focused on whether Austin and Little received improper benefits from agents, though that probe has since expanded into possible academic violations and caused plenty of embarrassment for a university that is sensitive about protecting its academic reputation.

Davis had suspended Austin indefinitely for violating team rules Wednesday.

"We are still working with the NCAA staff to resolve these eligibility issues," athletic director Dick Baddour said in a statement. "The NCAA is focusing on each of their situations on a case-by-case basis. Together we are working to determine their status in as thorough and fair a process as is possible."