RALEIGH, N.C. -- North Carolina athletic director Dick Baddour said Thursday the NCAA is investigating a sports program at the school regarding possible rules violations.

A source at North Carolina told ESPN.com's Joe Schad on Thursday that UNC football players were interviewed by the NCAA this week and asked questions about agents and whether anyone had received gifts or extra benefits.

Defensive tackle Marvin Austin, one of several Tar Heels who passed on the NFL draft this spring, was among the players interviewed, according to the source.

The source said the NCAA's questions to players were intended to "make sure no Reggie Bush stuff is going on."

Baddour declined to tell The Associated Press which sport was being probed.

"I was told that I could limit my comments to the fact that they had been here and they wanted me to say that we had indeed been cooperative," said Baddour, adding that the inquiry "has our full attention."

The investigation began with a phone call from the NCAA, Baddour said, though he declined to say when the call came or when investigators had visited the Chapel Hill campus.

"We work hard on our compliance program, a program of integrity," Baddour said. "We're proud of it. We are also proud that, or we think very strongly that, we get an inquiry from the NCAA that we would comply, we would do what they asked us to do and we would do it forthright and completely."

A second source said that the NCAA asked all of UNC's projected NFL draft picks to provide phone records so investigators could see which agents they had spoken with.

The players were also asked who paid for the travel, who paid their rent and which agents they had met with and when, according to the second source.

Austin recently tweeted about a trip to Miami.

Both sources used the word "hectic" to describe the agent activity surrounding North Carolina football since multiple players passed on the NFL draft.

A third source, with ties to North Carolina, said that Austin was asked about having been seen driving Kentwan Balmer's vehicle.

Balmer is a former North Carolina defensive end who plays for the 49ers and worked out in Chapel Hill this offseason. Another source said Austin stayed at Balmer's apartment at times this offseason as well.

Davis is preparing for his fourth season in Chapel Hill and has guided the program to consecutive eight-win seasons, including the program's first back-to-back bowl seasons since the late 1990s, when Mack Brown left for Texas.

Davis has a 20-18 record with the Tar Heels, including 11-13 in the Atlantic Coast Conference. When Davis inherited the program from John Bunting, the Tar Heels had gone to just two bowl games in six seasons, during which they were a woeful 27-45.

The Tar Heels are expected to contend for the ACC's Coastal Division title with a defense that returns nine starters from a unit that ranked among the nation's best last year. North Carolina opens the season against LSU in Atlanta on Sept. 4.

ESPN.com's Joe Schad and The Associated Press contributed to this report.